High Quality Content by WIKIPEDIA articles DeWitt County is a county located in the U.S. state of Illinois. According to the 2010 census, it has a population of 16,561, which is a decrease of 1.4% from 16,798 in 2000. Its name is in honor of the seventh Governor of New York State, DeWitt Clinton. Its county seat is Clinton. The U.S. Census Bureau and the USGS list the county's name as De Witt, although the county uses the name DeWitt (no space)...