Decatur /dəˈkeɪtər/ is the largest city and the county seat of Macon County in the U.S. state of Illinois, with a population of 76,122 as of the 2010 Census. The city was founded in 1829 and is situated along the Sangamon River and Lake Decatur in Central Illinois. Decatur’s estimated population for 2018 was 71,290.
The USGS Domestic GeoNames resource has two listings for Decatur: “City of Decatur”, which is a Civil-class designation, and “Decatur”, which is a Populated Place designation, which have slightly different coordinate centroids: “City of Decatur” centroid is located at 39°51′20″N 88°56′01″W / 39.8556417°N 88.9337090°W / 39.8556417; -88.9337090, while the “Decatur” centroid is at 39°50′25″N 88°57′17″W / 39.8403147°N 88.9548001°W / 39.8403147; -88.9548001. Decatur is 180 miles southwest of Chicago, 40 miles east of Springfield, the state capital, and 115 miles northeast of St. Louis.
According to the 2010 census, consisted of 42.22 square miles (109.35 km) land and 4.69 square miles (12.15 km) of water, together amounting to a total area of 46.91 square miles (121.50 km), consisting of 90% land and 10% water. Lakes include Lake Decatur, an 11 km reservoir formed in 1923 by the damming of the Sangamon River, accounting for >90% of the state’s census-designated water area.
The Decatur Metropolitan Statistical Area (population 109,900) includes surrounding towns of Argenta, Boody, Blue Mound, Elwin, Forsyth, Harristown, Long Creek, Macon, Maroa, Mount Zion, Niantic, Oakley, Oreana, and Warrensburg.
As of the 2010 census, there were 76,122 people, 32,344 households, and 18,991 families residing in the city. The population density was 1,800.9 people per square mile (695.3/km²). There were 36,134 housing units at an average density of 854.8 per square mile (330.0/km²). The racial makeup of the city was 71.6% White, 23.3% African American, 0.2% Native American, 0.9% Asian, 0.9% from other races, and 3.1% from two or more races. Hispanic or Latino people of any race were 2.2% of the population.
There were 32,344 households, out of which 24.2% had children under the age of 18 living with them, 37.4% were married couples living together, 16.9% had a female household with no husband present, and 41.3% were non-families. 35.2% of all households were made up of individuals and 13.2% had someone living alone who was 65 years of age or older. The average household size was 2.23 and the average family size was 2.86.
In the city, the population was spread out with 22.1% under the age of 18, 10.8% from ages 18 to 24, 23.4% from ages 25 to 44, 26.8% from ages 45 to 64, and 16.9% who were 65 years of age or older. The median age was 39.1 years. For every 100 females, there were 88.0 males. For every 100 females aged 18 and over, there were 85.3 males.
As of 2017, the median income for a household in the city was $41,977, and the median income for a family was $55,086. Males had a median income of $35,418 versus $34,389 for females. The per capita income for the city was $25,042. About 22% of the population is below the poverty line, including 35% of those under age 18 and 10% of those age 65 or over.