Chatham is a village in Sangamon County, Illinois, United States. It is located 2.8 miles south of Springfield and has a retail trade area that extends into four other municipalities, including Springfield. The population was 11,500 as of the 2010 census and estimated to be 13,008 as of 2019. The village lies along the original alignment of historic U.S. Route 66 (Illinois Route 4).
Chatham is part of the Springfield, Illinois Metropolitan Statistical Area.
Chatham is located at 39°40′22″N 89°41′54″W (39.672899, -89.698385). According to the 2010 census, Chatham has a total area of 5.722 square miles (14.82 km2), of which 5.72 square miles (14.81 km2) (or 99.97%) is land and 0.002 square miles (0.01 km2) (or 0.03%) is water.
As of the census of 2010, the racial makeup of the village was 93.57% White, 2.47% African American, 0.09% Native American, 1.85% Asian, 0.46% from other races, and 1.57% from two or more races. Hispanic or Latino of any race were 1.97% of the population.
As of the census of 2000, there were 8,583 people, 3,083 households, and 2,472 families residing in the village. The population density was 1,728.7 people per square mile (666.8/km²).