Redistricting in Illinois

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Redistricting in Illinois
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General information
Current legislative control:
Congressional process:
State legislature
State legislature process:
State legislature[1]
Total seats
Congress: 18
State Senate: 59
State House: 118
Redistricting in other states
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RedistrictingState-by-state redistricting proceduresState legislative and congressional redistricting after the 2010 Census
Redistricting is the process by which new congressional and state legislative district boundaries are drawn. Each of Illinois' 18 United States Representatives and 177 state legislators are elected from political divisions called districts. United States Senators are not elected by districts, but by the states at large. District lines are redrawn every 10 years following completion of the United States Census. The federal government stipulates that districts must have nearly equal populations and must not discriminate on the basis of race or ethnicity.

Redistricting is a fiercely-contested issue, primarily due to gerrymandering, the practice of drawing district lines to favor one political party, individual or constituency over another. Two areas of contention include the following:

Competitiveness: Political parties or incumbents sometimes draw district lines for their benefit at the expense of proportionality and fair representation. Some argue that this practice contributes to the present lack of competitive elections. Uncompetitive elections can in turn discourage participation.[2]
Race and ethnicity: District lines sometimes minimize the influence of minority voters by disproportionately consolidating them within single districts or splitting them across several districts. These practices are examples of "packing" and "cracking," respectively.[2][3][4][5]
In Illinois, the state legislature is responsible for drawing both congressional and state legislative districts. In 2014, 12 elections for the United States House of Representatives were won by margins of victory of 20 percent or greater. The smallest margin of victory was 2.6 percent. An election is considered competitive if the margin of victory is 5 percent or less.


See also: Redistricting

Federal law stipulates that all districts, whether congressional or state legislative, must meet two primary criteria.

  1. Equal population: According to All About Redistricting, federal law "requires that each district have about the same population: each federal district within a state must have about the same number of people [and] each state district within a state must have about the same number of people." Specific standards for determining whether populations are sufficiently equal vary for congressional and state legislative districts. See below for further details.[6]
  2. Race and ethnicity: Section 2 of the Voting Rights Act of 1965 states that district lines must not dilute the voting power of racial or ethnic minority groups. This provision "applies whether the denial is intentional, or an unintended end result. Courts essentially test whether the way that districts are drawn takes decisive political power away from a cohesive minority bloc otherwise at risk for discrimination."[6]

In most states, the legislatures are primarily responsible for both congressional and state legislative redistricting. However, reformers argue that partisan legislators are incapable of establishing fair district lines because they have a vested interest in the outcome. Instead, reformers advocate using different redistricting processes, including independent commissions or electronic methods. Opponents of these reforms argue that alternative processes are less accountable to voters, subject to partisan abuse, and perhaps unconstitutional.

State requirements


In addition to the federal criteria noted above, individual states may impose additional requirements on redistricting. Common state-level redistricting criteria are listed below. Typically, these requirements are quite flexible.

  1. Contiguity refers to the principle that all areas within a district should be "physically adjacent." A total of 49 states require that districts of at least one state legislative chamber be contiguous. A total of 23 states require that congressional districts meet contiguity requirements.[6][7]
  2. Compactness refers to the general principle that "the distance between all parts of a district" ought to be minimized. The United States Supreme Court has "construed compactness to indicate that residents have some sort of cultural cohesion in common." A total of 37 states "require their legislative districts to be reasonably compact." A total of 18 states impose similar requirements for congressional districts.[6][7]
  3. A community of interest is a "group of people in a geographical area, such as a specific region or neighborhood, who have common political, social or economic interests." A total of 24 states require that the maintenance of communities of interest be considered in the drawing of state legislative districts. A total of 13 states impose similar requirements for congressional districts.[6][7]
  4. A total of 42 states require that state legislative district lines be drawn to account for political boundaries (e.g., the limits of counties, cities and towns). A total of 19 states require that similar considerations be made in the drawing of congressional districts.[6][7]

Congressional redistricting

According to Article 1, Section 4, of the United States Constitution, the states and their legislatures have primary authority in determining the "times, places and manner" of congressional elections. Congress may also pass laws regulating congressional elections. Section 4 explicitly vests the authority to regulate congressional elections with the legislative branches of the states and the federal government and not with the executive or judicial branches.[8][9]

The Times, Places and Manner of holding Elections for Senators and Representatives, shall be prescribed in each State by the Legislature thereof; but the Congress may at any time by Law make or alter such Regulations, except as to the Places of chusing Senators.[10]

—United States Constitution

Article 1, Section 2, of the United States Constitution stipulates that congressional representatives be apportioned to the states on the basis of population. There are 435 seats in the United States House of Representatives. Each state is allotted a portion of these seats based on the size of its population relative to the other states. Consequently, a state may gain seats in the House if its population grows, or lose seats if its population decreases, relative to populations in other states. In 1964, the United States Supreme Court ruled in Wesberry v. Sanders that the populations of House districts must be equal "as nearly as practicable."[11][12][6]

The equal population requirement for congressional districts is strict. According to All About Redistricting, "any district with more or fewer people than the average (also known as the 'ideal' population), must be specifically justified by a consistent state policy. And even consistent policies that cause a 1 percent spread from largest to smallest district will likely be unconstitutional."[6]

State legislative redistricting

The United States Constitution is silent on the issue of state legislative redistricting. In the mid-1960s, the United States Supreme Court issued a series of rulings in an effort to clarify standards for state legislative redistricting. In Reynolds v. Sims, the court ruled that "the Equal Protection Clause [of the United States Constitution] demands no less than substantially equal state legislative representation for all citizens, of all places as well as of all races." According to All About Redistricting, "it has become accepted that a [redistricting] plan will be constitutionally suspect if the largest and smallest districts [within a state or jurisdiction] are more than 10 percent apart."

State process

See also: State-by-state redistricting procedures

In 37 states, legislatures are primarily responsible for drawing congressional district lines. Seven states have only one congressional district each, so congressional redistricting is not necessary. Four states employ independent commissions to draw the district maps. In two states, politician commissions draw congressional district lines.

State legislative district lines are primarily the province of the state legislatures themselves in 37 states. In seven states, politician commissions draw state legislative district lines. In the remaining six states, independent commissions draw the lines.[13]

The Illinois General Assembly is responsible for drawing both congressional and state legislative district lines. Both chambers of the state legislature must approve a redistricting plan. The governor may veto the lines drawn by the state legislature.[14]

In the event that both chambers of the state legislature do not approve a legislative redistricting plan, a backup commission must draw the lines. The majority and minority leaders of each chamber must appoint two members each to the commission (one legislator and one general citizen). Of the eight commission members, no more than four may belong to the same political party. In the event that these eight members cannot approve a plan, the Illinois Supreme Court must select two individuals (from different political parties) as potential tiebreakers. The secretary of state must then appoint one of these individuals to the backup commission to break the tie.[14]

The Illinois Constitution requires that state legislative districts be "contiguous and reasonably compact." There are no such requirements in place for the state's congressional districts.[14]

State law also mandates the establishment of state legislative districts "that allow racial or language minority communities to elect--or influence the election of--the candidates of their choice, even if no comparable district would be required by the federal Voting Rights Act."[14]

District maps

Congressional districts

See also: United States congressional delegations from Illinois
Click the above image to enlarge it.
Source: The National Atlas of the United States of America

Illinois comprises 18 congressional districts. The map to the right depicts Illinois' congressional district lines as drawn following the 2010 United States Census. The table below lists Illinois' current House representatives.

Illinois delegation to the United States House of Representatives
NamePartyPositionAssumed officeTerm ends
Adam KinzingerRepublican PartyDistrict 16 2011January 3, 2017
Bill FosterDemocratic PartyDistrict 11 2013January 3, 2017
Bobby L. RushDemocratic PartyDistrict 1 1993January 3, 2017
Cheri BustosDemocratic PartyDistrict 17 2013January 3, 2017
Daniel LipinskiDemocratic PartyDistrict 3 2005January 3, 2017
Danny K. DavisDemocratic PartyDistrict 7 1997January 3, 2017
Jan SchakowskyDemocratic PartyDistrict 9 1999January 3, 2017
John ShimkusRepublican PartyDistrict 15 1997January 3, 2017
Luis V. GutierrezDemocratic PartyDistrict 4 1993January 3, 2017
Mike BostRepublican PartyDistrict 12 2015January 3, 2017
Mike QuigleyDemocratic PartyDistrict 5 2009January 3, 2017
Peter J. RoskamRepublican PartyDistrict 6 2007January 3, 2017
Randy HultgrenRepublican PartyDistrict 14 2011January 3, 2017
Robert J. DoldRepublican PartyDistrict 10 2015January 3, 2017
Robin KellyDemocratic PartyDistrict 2 2013January 3, 2015
Rodney DavisRepublican PartyDistrict 13 2013January 3, 2017
Tammy DuckworthDemocratic PartyDistrict 8 2013January 3, 2017

State legislative maps

See also: Illinois State Senate and Illinois House of Representatives

Illinois comprises 59 state Senate districts and 118 state House districts. State senators are elected every four years in partisan elections. State representatives are elected every two years in partisan elections. To access images of the state legislative district maps, click here.[15]


There are conflicting opinions regarding the correlation between partisan gerrymandering and electoral competitiveness. Some critics contend that the dominant redistricting methods result in a lack of competitive elections. Jennifer Clark, a political science professor at the University of Houston, said, "The redistricting process has important consequences for voters. In some states, incumbent legislators work together to protect their own seats, which produces less competition in the political system. Voters may feel as though they do not have a meaningful alternative to the incumbent legislator. Legislators who lack competition in their districts have less incentive to adhere to their constituents’ opinions."[16]

Some question the impact of redistricting on electoral competitiveness. In 2006, Emory University professors Alan Abramowitz, Brad Alexander and Matthew Gunning wrote, "[Some] studies have concluded that redistricting has a neutral or positive effect on competition. ... [It] is often the case that partisan redistricting has the effect of reducing the safety of incumbents, thereby making elections more competitive."[17]

The individuals involved in redistricting must balance the desire for increased competitiveness with other principles that might conflict with that goal, such as compactness, contiguity, and maintaining communities of interest. For instance, it may at times be impossible to draw a competitive district that is both compact and preserves communities of interest.

In 2011, James Cottrill, a professor of political science at Santa Clara University, published a study of the effect of "non-legislative approaches" to redistricting on the competitiveness of congressional elections. Cottrill found that "particular types of [non-legislative approaches] encourage the appearance in congressional elections of experienced and well-financed challengers." Cottrill cautioned, however, that non-legislative approaches "contribute neither to decreased vote percentages when incumbents win elections nor to a greater probability of their defeat."[18]


See also: Margin of victory analysis for the 2014 congressional elections

In 2014, Ballotpedia analyzed the margins of victory in all 435 contests for the United States House of Representatives. Ballotpedia found that the average margin of victory was 35.8 percent, compared to 31.8 percent in 2012. An election is deemed competitive if it was won by a margin of victory of 5 percent or less. A total of 318 elections (73 percent of all House elections) were won by margins of victory of 20 percent or more. Only 26 elections (6 percent of the total) were won by margins of victory of 5 percent or less. See the table below for further details.

Note: The data below are provided only for informational purposes. It should be noted that there are conflicting opinions regarding the correlation between redistricting and competitiveness. A variety of factors at the local, state and federal levels can impact electoral competitiveness.

In Illinois, 12 elections for the United States House of Representatives were won by margins of victory of 20 percent or greater. The smallest margin of victory occurred in District 10, where Bob Dold Jr. (R) won by 2.6 percent. The largest margin of victory occurred in District 7, where Danny K. Davis (D) won by 70.2 percent. The average margin of victory was 32.7 percent. See the table below for full details.

Electoral margins of victory in 2014 United States House of Representatives elections, Illinois
District Winner Margin of victory Total votes cast Top opponent
District 1 Democratic Party Bobby Rush 46.2% 222,017 Jimmy Lee Tillman
District 2 Democratic Party Robin Kelly 57.1% 204,266 Eric Wallace
District 3 Democratic Party Dan Lipinski 29.1% 180,855 Sharon Brannigan
District 4 Democratic Party Luis Gutierrez 56.3% 101,944 Hector Concepcion
District 5 Democratic Party Mike Quigley 32.6% 184,019 Vince Kolber
District 6 Republican Party Peter Roskam 34.3% 238,743 Michael Mason
District 7 Democratic Party Danny K. Davis 70.2% 182,278 Robert Bumpers
District 8 Democratic Party Tammy Duckworth 11.5% 151,056 Lawrence Kaifesh
District 9 Democratic Party Jan Schakowsky 32.1% 213,450 Susanne Atanus
District 10 Republican Party Bob Dold Jr. 2.6% 187,128 Brad Schneider
District 11 Democratic Party Bill Foster 6.9% 174,771 Darlene Senger
District 12 Republican Party Mike Bost 10.6% 209,738 Bill Enyart
District 13 Republican Party Rodney Davis 17.3% 210,272 Ann Callis
District 14 Republican Party Randy Hultgren 30.8% 222,230 Dennis Anderson
District 15 Republican Party John Shimkus 49.8% 221,926 Eric Thorsland
District 16 Republican Party Adam Kinzinger 41.2% 217,198 Randall Olsen
District 17 Democratic Party Cheri Bustos 10.9% 199,345 Bobby Schilling
District 18 Republican Party Aaron Schock 49.5% 247,013 Darrel Miller

State legislatures

See also: Margin of victory in state legislative elections

In 2014, Ballotpedia conducted a study of competitive districts in 44 state legislative chambers between 2010 and 2012. Ballotpedia found that there were 61 fewer competitive general election contests in 2012 than in 2010. Of the 44 chambers studied, 25 experienced a net loss in the number of competitive elections. A total of 17 experienced a net increase. In total, 16.2 percent of the 3,842 legislative contests studied saw competitive general elections in 2010. In 2012, only 14.6 percent of the contests studied saw competitive general elections. An election was considered competitive if it was won by a margin of victory of 5 percent or less. An election was considered mildly competitive if it was won by a margin of victory between 5 and 10 percent. For more information regarding this report, including methodology, click here.

Note: These data are provided only for informational purposes. It should be noted that there are conflicting opinions regarding the correlation between redistricting and competitiveness. A variety of factors at the local, state and federal levels can impact electoral competitiveness.

There were four competitive races in the Illinois House of Representatives in 2012, the same as in 2010. There were only two mildly competitive races for the state House in 2012, compared to six in 2010. This amounted to a net loss of four competitive races.

Partisan composition

The tables below summarize the current partisan composition of the Illinois House of Representatives and the Illinois State Senate.


SLP badge.png
Party As of May 2015
     Democratic Party 71
     Republican Party 47
Total 118


Party As of May 2015
     Democratic Party 39
     Republican Party 20
Total 59

Race and ethnicity

See also: Majority-minority districts

Section 2 of the Voting Rights Act of 1965 mandates that electoral district lines cannot be drawn in such a manner as to "improperly dilute minorities' voting power."

No voting qualification or prerequisite to voting, or standard, practice, or procedure shall be imposed or applied by any State or political subdivision to deny or abridge the right of any citizen of the United States to vote on account of race or color.[10]

—Voting Rights Act of 1965[19]

States and other political subdivisions may create majority-minority districts in order to comply with Section 2 of the Voting Rights Act. A majority-minority district is a district in which minority groups comprise a majority of the district's total population. As of 2013, Illinois was home to four congressional majority-minority districts: District 1, District 2, District 4 and District 7.[3][4][5]

Proponents of majority-minority districts maintain that these districts are a necessary hindrance to the practice of "cracking." Cracking occurs when a constituency is divided between several districts in order to prevent it from achieving a majority in any one district. In addition, supporters argue that the drawing of majority-minority districts has resulted in an increased number of minority representatives in state legislatures and Congress.[3][4][5]

Critics, meanwhile, contend that the establishment of majority-minority districts results in "packing." Packing occurs when a constituency or voting group is placed within a single district, thereby minimizing its influence in other districts. Because minority groups tend to vote Democratic, critics argue that majority-minority districts ultimately present an unfair advantage to Republicans by consolidating Democratic votes into a smaller number of districts.[3][4][5]


See also: Demographics of congressional districts as of 2013 and Demographics of congressional districts as of 2013 (as percentages)

The tables below provide demographic information for each of Illinois's congressional districts as of 2013. At that time, the population of the largest congressional district, District 5, totaled 725,210, and the population of the smallest, District 4, totaled 703,545, which represented a difference of 3.1 percent.[20]

Demographics of Illinois's congressional districts (as percentages)
District Hispanic White Black Native
Asian Pacific
Other Multiple
Illinois 16.04% 63.25% 14.20% 0.11% 4.71% 0.02% 0.13% 1.53%
District 1 9.1% 35.5% 52.1% 0.1% 1.9% 0% 0.1% 1.2%
District 2 13% 29.4% 55.2% 0.1% 0.7% 0% 0.1% 1.5%
District 3 29.6% 61.1% 4.4% 0.1% 3.7% 0% 0.1% 1%
District 4 70.7% 21.5% 4% 0.1% 2.7% 0% 0.1% 0.9%
District 5 19.1% 69.5% 2.7% 0.1% 6.8% 0% 0.2% 1.6%
District 6 9.1% 79.1% 2.2% 0.1% 7.9% 0% 0.1% 1.4%
District 7 13% 27% 52.3% 0.1% 6% 0% 0.2% 1.3%
District 8 27.2% 54.5% 4.7% 0.1% 12% 0% 0.1% 1.5%
District 9 11.4% 65.1% 8.5% 0.1% 12.5% 0% 0.2% 2.1%
District 10 21.6% 60.6% 6.4% 0.1% 9.4% 0% 0.2% 1.7%
District 11 26.1% 53.7% 10.7% 0.1% 7% 0% 0.3% 2%
District 12 3% 77.1% 16.6% 0.2% 1% 0% 0.1% 1.9%
District 13 3% 80.4% 11% 0.1% 3.5% 0% 0.1% 1.9%
District 14 11.4% 80% 2.9% 0.1% 4.1% 0% 0.1% 1.3%
District 15 2.5% 91.2% 4.1% 0.1% 0.6% 0% 0.1% 1.5%
District 16 8.4% 85.4% 3.5% 0.1% 1.4% 0% 0.1% 1.3%
District 17 8.5% 77.2% 10.9% 0.2% 1.1% 0% 0.1% 1.9%
District 18 2.5% 89.7% 3.7% 0.1% 2.3% 0% 0.1% 1.5%
Source: United States Census Bureau, "2009-2013 American Community Survey 5-Year Estimates," accessed April 8, 2015
Demographics of Illinois's congressional districts
District Hispanic White Black Native
Asian Pacific
Other Multiple
Illinois 2,060,706 8,126,804 1,825,101 14,733 605,095 2,446 17,221 196,448 12,848,554
District 1 65,276 255,068 373,992 1,023 13,397 61 599 8,306 717,722
District 2 92,644 209,114 392,746 743 4,879 46 791 10,481 711,444
District 3 212,447 437,924 31,512 608 26,581 6 880 7,141 717,099
District 4 497,724 150,937 27,849 393 19,303 204 847 6,288 703,545
District 5 138,673 504,143 19,230 1,015 49,501 134 1,166 11,348 725,210
District 6 65,406 566,676 16,008 387 56,789 118 923 10,362 716,669
District 7 92,851 192,497 372,983 700 42,712 144 1,480 9,428 712,795
District 8 194,210 389,502 33,386 669 85,565 235 856 10,440 714,863
District 9 81,700 466,291 61,061 854 89,407 108 1,525 15,226 716,172
District 10 153,523 431,595 45,337 928 66,850 79 1,189 12,338 711,839
District 11 186,668 384,352 76,316 660 50,235 123 2,261 14,526 715,141
District 12 21,358 548,002 118,227 1,463 7,172 162 485 13,623 710,492
District 13 21,175 570,746 77,878 988 24,618 126 863 13,790 710,184
District 14 81,900 575,569 20,585 567 29,786 345 753 9,706 719,211
District 15 17,406 647,554 29,108 1,025 4,252 99 463 10,495 710,402
District 16 59,485 605,224 24,470 620 9,689 116 405 8,921 708,930
District 17 60,121 548,084 77,694 1,353 7,914 243 912 13,263 709,584
District 18 18,139 643,526 26,719 737 16,445 97 823 10,766 717,252
Source: United States Census Bureau, "2009-2013 American Community Survey 5-Year Estimates," accessed April 8, 2015

Redistricting after the 2010 census

See also: Redistricting in Illinois after the 2010 census

Following the completion of the 2010 United States Census, Illinois lost one congressional seat. At the time of redistricting, Democrats held majorities in both chambers of the state legislature. On May 30, 2011, the Illinois House of Representatives approved a congressional redistricting plan. The Illinois State Senate approved the plan on May 31, 2011 and Governor Pat Quinn (D) signed it into law on June 24, 2011. Some argued that the maps had been improperly drawn to threaten Republican incumbents. In 2010, Republicans had won a majority of Illinois' House seats. Legal suits were filed challenging the new congressional district map, but these were all ultimately dismissed.[21][22][14]

The state legislative redistricting plan was passed by the legislature on May 27, 2011. Quinn signed the map into law on June 3, 2011. As with the congressional map, lawsuits were filed challenging the new state legislative districts. These suits were ultimately dismissed.[14]

Redistricting after the 2000 census

As a result of the 2000 United States Census, Illinois lost one congressional seat. At the time of redistricting, control of the Illinois General Assembly was split; Democrats held a majority in the Illinois House of Representatives and Republicans held a majority in the Illinois State Senate. According to The Almanac of American Politics, legislative leaders from both sides of the aisle "fashioned a [congressional] plan to protect every incumbent except one unlucky junior Democrat in far downstate Illinois." In spite of legislators' efforts to maintain the status quo, "the map produced a fair share of competition: Democrats, who held 12 of 19 seats after 2008, fell to just eight after 2010."[23]

Redistricting ballot measures

Voting on
elections and campaigns
Ballot measures
By state
By year
Not on ballot
See also: Redistricting measures on the ballot and List of Illinois ballot measures

Ballotpedia has tracked the following ballot measure(s) relating to redistricting in Illinois.

  1. Illinois Independent Redistricting Amendment (2014)

Recent news

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See also

External links

Additional reading


  1. A backup commission draws state legislative district lines in the event that the legislature cannot approve a plan.
  2. 2.0 2.1 All About Redistricting, "Why does it matter?" accessed April 8, 2015
  3. 3.0 3.1 3.2 3.3 Indy Week, "Cracked, stacked and packed: Initial redistricting maps met with skepticism and dismay," June 29, 2011
  4. 4.0 4.1 4.2 4.3 The Atlantic, "How the Voting Rights Act Hurts Democrats and Minorities," June 17, 2013
  5. 5.0 5.1 5.2 5.3 Redrawing the Lines, "The Role of Section 2 - Majority Minority Districts," accessed April 6, 2015
  6. 6.0 6.1 6.2 6.3 6.4 6.5 6.6 6.7 All About Redistricting, "Where are the lines drawn?" accessed April 9, 2015
  7. 7.0 7.1 7.2 7.3 FairVote, "Redistricting Glossary," accessed April 9, 2015
  8. The Heritage Guide to the Constitution, "Election Regulations," accessed April 13, 2015
  9. Brookings, "Redistricting and the United States Constitution," March 22, 2011
  10. 10.0 10.1 Note: This text is quoted verbatim from the original source. Any inconsistencies are attributed to the original source.
  11. Brennan Center for Justice, "A Citizen's Guide to Redistricting," accessed March 25, 2015
  12. The Constitution of the United States of America, "Article 1, Section 2," accessed March 25, 2015
  13. All About Redistricting, "Who draws the lines?" accessed March 25, 2015
  14. 14.0 14.1 14.2 14.3 14.4 14.5 All About Redistricting, "Illinois," accessed April 16, 2015
  15. Illinois Redistricting, "2011 Adopted Maps," accessed April 17, 2015
  16. The Daily Cougar, "Redistricting will affect November election," October 16, 2012
  17. The Journal of Politics, "Incumbency, Redistricting, and the Decline of Competition in U.S. House Elections," February 2006
  18. Polity, "The Effects of Non-Legislative Approaches to Redistricting on Competition in Congressional Elections," October 3, 2011
  19. Yale Law School, The Avalon Project, "Voting Rights Act of 1965; August 6, 1965," accessed April 6, 2015
  20. United States Census Bureau, "2009-2013 American Community Survey 5-Year Estimates," accessed April 8, 2015
  21. The Huffington Post, "Illinois Redistricting: Quinn Signs Plan To Add Democratic Seats," June 24, 2011
  22. The Huffington Post, "Illinois Redistricting: Democrat-Backed Maps Head To Quinn's Desk, Threaten Republican Gains," May 31, 2011
  23. Barone, M. & McCutcheon, C. (2013). The almanac of American politics 2014 : the senators, the representatives and the governors : their records and election results, their states and districts. Chicago, IL: University of Chicago Press.