Mercer County is a county in Illinois. Seven years after Illinois became a state, Mercer County was founded. It was formed from unorganized territory near Pike County on January 13, 1825.
- Main article: Evaluation of Illinois county websites
Mercer County has a small website that is growing, but currently posts little information.
- The website lists council members and their contact information.
- The site fails to include any concrete information, only plans from 2003-2008.
- The site fails to include a way to file a public records request.
- Main article: Illinois government sector lobbying
Mercer County does not have contracts with lobbyists. It belonged to 17 government sector lobbying associations between 2005-2010, and spent $19,450.21 on membership dues to those organizations. 
Cities and towns
Mercer County is divided into fifteen townships:
- Abington Township
- Duncan Township
- Eliza Township
- Greene Township
- Keithsburg Township
- Mercer Township
- Millersburg Township
- New Boston Township
- North Henderson Township
- Ohio Grove Township
- Perryton Township
- Preemption Township
- Richland Grove Township
- Rivoli Township
- Suez Township
List of school districts in the county
- Aledo Community Unit School District 201
- Westmer Community Unit School District 203
- Sherrard Community Unit School District 200