south side of the ridge drains to tributaries of Sugar Creek, which flows southeast to the Oconee River, while the north side drains via Mill Branch to Hard Labor Creek, an east-flowing tributary of the Apalachee River, which continues to the Oconee. The southwest part of the city drains to Little Indian Creek, a tributary of the Little River, which flows to the Oconee north of Milledgeville. Interstate 20, U.S. Route 129, U.S. Route 441, and U.S. Route 278 pass through Madison. I-20 serves the city from exits 113 and 114, leading east to Augusta and west to Atlanta. U.S. 278 runs through the center of the city, leading east to Greensboro and west to Covington. U.S. 129/441 run through the city together, leading north to Athens and south to Eatonton. Demographics 2020 census As of the 2020 United States Census, there were 4,447 people, 1,625 households, and 1,121 families residing in the city. 2000 census As of the census of 2000, there were 3,636 people, 1,362 households, and 964 families residing in the city. The population density was . There were 1,494 housing units at an average density of . The racial makeup of the city was 48.93% White, 47.83% African-American, 0.08% Native American, 0.99% Asian, 1.10% from other races, and 1.07% from two or more races. Hispanic or Latino of any race were 2.09% of the population. There were 1,362 households, out of which 32.0% had children under the age of 18 living with them, 44.0% were married couples living together, 22.6% had a female householder with no husband present, and 29.2% were non-families. 25.2% of all households were made up of individuals, and 10.7% had someone living alone who was 65 years of age or older. The average household size was 2.61 and the average family size was 3.11. In the city, the population was spread out, with 26.1% under the age of 18, 7.4% from 18 to 24, 28.2% from 25 to 44, 22.4% from 45 to 64, and 15.9% who were 65 years of age or older. The median age was 37 years. For every 100 females, there were 84.3 males. For every 100 females age 18 and over, there were 77.9 males. The median income for a household in the city was $36,055, and the median income for a family was $40,265. Males had a median income of $40,430 versus $21,411 for females. The