Sangamon County is a county located near the center of the U.S. state of Illinois. According to the 2020 census, it had a population of 196,343. Its county seat and largest city is Springfield, the st

Menard County is a county in the U.S. state of Illinois. According to the 2020 United States census, it had a population of 12,297. Its county seat is Petersburg. Menard County is part of the Springfi