| Hamilton County Illinois Cities/Towns - Belle Prairie City, Broughton, Dahlgren, Dale, McLeansboro (County Seat) |
![]() |
Your Ad Here Hamilton County is a county located in the U.S. state of Illinois. As of 2000, the population was 8,621. Its county seat is McLeansboro. History Hamilton County was formed in 1821. It is named for Alexander Hamilton, Revolutionary War hero and the first United States Secretary of the Treasury. ![]() |