Pike County, Illinois
Pike County is a county in the U.S. state of Illinois. According to the 2010 United States Census, it had a population of 16,430. Its county seat is Pittsfield. History. Pike County was formed in January 1821 out of Madison County. It was named in honor of Zebulon Pike, leader of the Pike Expedition in 1806 to map out the south and west portions of the Louisiana Purchase. Pike served at the Battle of Tippecanoe, and was killed in 1813 in the War of 1812. Prior to the coming of the first European settler to the future  Pike County, French traders, hunters, and travelers passed through the native forests and prairies. Originally Pike County began on the south junction of the Illinois and Mississippi rivers. The east boundary was the Illinois River north to the Kankakee River to the Indiana State line on north to Wisconsin territorial line and then west to the Mississippi River to the original point at the south end. The first county seat was Cole's Grove, a post town, in what later became Calhoun County. "The Gazetteer of Illinois and Missouri", published in 1822, mentioned Chicago as "a village of Pike County