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 11,946 as of 2012. The village lies along the original alignment of historic U.S. Route 66 (Illinois Route 4).
Chatham is located at 39°40′22″N 89°41′54″W / 39.67278°N 89.69833°W / 39.67278; -89.69833 (39.672899, -89.698385). According to the 2010 census, Chatham has a total area of 5.722 square miles (14.82 km), of which 5.72 square miles (14.81 km) (or 99.97%) is land and 0.002 square miles (0.01 km) (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). There were 3,165 housing units at an average density of 637.4 per square mile (245.9/km²). The racial makeup of the village was 97.48% White, 0.77% African American, 0.15% Native American, 0.90% Asian, 0.15% from other races, and 0.55% from two or more races. Hispanic or Latino of any race were 0.77% of the population.
There were 3,083 households out of which 47.4% had children under the age of 18 living with them, 65.9% were married couples living together, 11.1% had a female householder with no husband present, and 19.8% were non-families. 16.5% of all households were made up of individuals and 4.7% had someone living alone who was 65 years of age or older. The average household size was 2.78 and the average family size was 3.13.
In the village, the population was spread out with 32.0% under the age of 18, 6.5% from 18 to 24, 31.7% from 25 to 44, 22.6% from 45 to 64, and 7.2% who were 65 years of age or older. The median age was 35 years. For every 100 females, there were 96.4 males. For every 100 females age 18 and over, there were 90.6 males.
The median income for a household in the village was $60,350, and the median income for a family was $64,257. Males had a median income of $45,543 versus $31,883 for females. The per capita income for the village was $23,167. About 2.8% of families and 4.7% of the population were below the poverty line, including 5.2% of those under age 18 and 5.6% of those age 65 or over.