  clinton county is a county located in the u.s. state of illinois. as of the 2010 census, the population was 37,762. its county seat is carlyle. in 1960, the u.s. census bureau placed the mean center of u.s. population in clinton county. clinton county is part of the st. louis, mo-il metropolitan statistical area. ==history==  in 1805, prior to the establishment of the county, the territorial government established a post road from its capital (vincennes, indiana) to st. louis, missouri, passing through the county. in 1808 a wagon road was laid out through what is now clinton county. the road extended from the goshen settlement to the ohio salt works and crossed the kaskaskia river at carlyle."" 1913 commercial history of clinton county, illinois from clinton.ilgenweb.net. retrieved 10 nov 2010 clinton county was organized in 1824 out of washington, fayette, and bond counties. it was named in honor of the seventh governor of new york, dewitt clinton, who helped build the erie canal.allan h. keith, historical stories: about greenville and bond county, il. retrieved august 15, 2007. crossing the kaskaskia became much easier when the bridge now known as the general dean suspension bridge was built in 1859, at a cost o
1824_establishments_in_Illinois Illinois_counties Little_Egypt Metro-East Populated_places_established_in_1824