The Greens have been active as a third party since 2001. The party first gained widespread public attention during Ralph Nader's presidential runs in 1996 and 2000. Currently, the primary national Green Party organization in the U.S. is the Green Party of the United States, which has eclipsed the earlier Greens/Green Party USA.
The Green Party in the United States has won elected office mostly at the local level; most winners of public office in the United States who are considered Greens have won nonpartisan-ballot elections (that is, the winning Greens won offices in elections in which candidates were not identified on the ballot as affiliated with any political party). The highest-ranking Greens ever elected in the nation were Richard Carroll  who is a member of the Arkansas House of Representatives elected in 2008, John Eder who was a member of the Maine House of Representatives 2002-2006, and Audie Bock, who was elected to the California State Assembly in 1999 but switched her registration to Independent seven months later running as an independent in the 2000 election. In 2005, the Party had 305,000 registered members in states that allow party registration, as well as tens of thousands of members and contributors in the rest of the country. During the 2006 elections the party had ballot access in 31 states.
In some states, the Green Party has affiliates under different names.
The Mountain Party came into existence as a ballot-qualified political party in 2000, when novelist Denise Giardina ran for Governor of West Virginia as a candidate of the party and won more than 1% of the vote. West Virginia's election laws say that when a party's candidate for governor achieves 1% or more of the vote for governor in the most recent general election, the party will be defined as ballot-qualified and can run candidates under its ballot label.
- Jesse Clarence Johnson Jr., candidate for U.S. Senate, in the special election to replace Robert Byrd, and for District 32, West Virginia House of Delegates
- David Bruce Hall, candidate for District 17, West Virginia State Senate
- Mark Steven Myers, candidate for District 11, West Virginia House of Delegates
Progressive Party of Missouri
The Progressive Party of Missouri is the official affiliate of the Green Party in the State of Missouri. The Progressive Party of Missouri has a platform that is compatible with the by-laws of the national Green Party.
- Midge Potts, candidate for the United States Senate seat vacated by the retirement of Kit Bond.
- Nicholas Ladendorf, candidate for United States Congress in Missouri's 7th District.
The Progressive Party of Missouri did not qualify any candidates for state legislature on the 2010 ballot.
The Green Party is fielding a total of 69 candidates for State House across the nation in 2010. The Green Party has qualified state house candidates in 17 states. The Green Party is also fielding 5 candidates that qualified on the ballot for State Senate in 4 states. The Green Party accounts for 0.62% of State House candidates and 0.18% of State Senate candidates in 2010.
- See also: Gubernatorial elections, 2010
- List of political parties in the United States
- Political parties with candidates in state senate elections in 2010
- Green Party of the United States Official website
- Green Senatorial Campaign Committee (GSCC) Official website
- National Lavender Greens Caucus (GLBTIQ)
- National Women's Caucus (NWC)
- Disability Caucus Identity Caucus of the United States Green Party
- Campus Greens
- Website of the Mountain Party (West Virginia affiliate of the Green Party)
- Green Party members holding elected office in the United States Green Party of California, June 2007
- Sole Green Party Legislator Makes Switch RAND California Policy Bulletin, Oct. 18, 1999
- Ca 2000 Election Night Returns (PDF) The Capital Connection, Nov. 08, 2000
- Green Party Ballot Status and Voter Registration Totals (United States) Green Party of California, May 2005
- Greens Win Ballot Access in 31 States, Up From 17 in January Green Party of the United States, Sep. 05, 2006
- Independent Political Report, "Mountain Party Primary Turnout is Better than Primary Turnout for Either Major Party in West Virginia", August 28, 2010
- Archive of the Denise Giardina for Governor website
- Candidates in the May 11, 2010 primary in West Virginia
- Green Party of Missouri "Welcome to the Progressive Party of Missouri"
- The Progressive Party of Missouri "About the PPMO"
- Politics1 "Missouri"
- Missouri Secretary of State "2010 Candidate List"