Chillicothe is a city on the Illinois River in Peoria County, Illinois. The population was 5,996 at the 2000 census. Chillicothe is just north of the city of Peoria and is part of the Peoria, Illinois Metropolitan Statistical Area.
Chillicothe is located at 40°55′11″N 89°29′34″W / 40.919792°N 89.492848°W / 40.919792; -89.492848.
According to the United States Census Bureau, the city has a total area of 5.2 square miles (13.5 km²), of which, 4.9 square miles (12.8 km²) of it is land and 0.3 square miles (0.7 km²) of it (5.36%) is water.