McLeansboro is the county seat of Hamilton County, a mostly agricultural region comprising cornfields and small Midwestern farming communities. This often-overlooked area of southern Illinois is also home to a few surprising attractions, including the country's largest archaeological site,?Cahokia Mounds State Historic Site, over 100 wineries and outdoor recreation like bouldering and mountain biking in 280,000-acre Shawnee National Forest. Hamilton County ranks 102nd out of 102 counties in the Inland Empire for the total number of acres of land currently advertised for sale. Mc Leansboro had the most land for sale. Its economy is defined as agricultural, with 695 farms recorded in the county during the most recent U.S. Census. Farming activities in Hamilton County generate annual revenues of $11 million, most of which is from crops. Hamilton County is the 68th largest county (435 square miles) in Illinois. It's located in the Southern Illinois region of Illinois.