Thomas Carlin, sixth elected Governor of Illinois from 1838 to 1842, was an early settler of Illinois and a prominent figure in organizing Greene County and establishing Carrollton as its county seat in 1821. Born in Kentucky in 1789, he came to the Illinois Territory and served in the War of 1812. He settled on farmland, part of which is now Carrollton. He served as the county's first sheriff in 1821, as a captain in the Black Hawk Militia in 1832, as a state senator from 1825 to 1833, and as a land office receiver in 1834. He died in 1852 and is buried in Carrollton City Cemetery.