States Census Bureau, the CDP has a total area of , of which is land and , or 0.82%, is water. Nickajack Creek, a tributary of the Chattahoochee, runs near the Smyrna-Mableton line. Mableton and most of Atlanta is in the Piedmont region, characterized by rolling hills and gentle slopes that make for narrow roads. Demographics 2020 census As of the 2020 United States census, there were 40,834 people, 14,465 households, and 10,945 families residing in the CDP, with a population density of 1,804.5 people per square mile. Mableton is the most populous unincorporated census-designated place (CDP) in the Metro Atlanta area. East Cobb - with a population estimate of around 208,000 in 2019 - is technically the most populous unincorporated area in the metro, though it is not recognized as a CDP in the Census Bureau. 2018 ACS The 5-year estimates of the 2018 ACS state that 39.2% of the population was White, 48.5% African American, 0.2% Native American/Alaska Native, 2.2% Asian, 0.0% Native Hawaiian/Pacific Islander, 6.2% from some other race alone, and 3.7% from two or more races. Hispanic or Latino of any race were 18.0% of the population. Individuals who identified as White alone, not Hispanic or Latino, were 30.3% of the population. There were 2,115 identified veterans in the area as of 2018. Foreign born persons (non-U.S. citizens or U.S. nationals at birth) made up 18.1% of the population. As of 2018, the median income for a household in the CDP was $64,790. Males had a median income of $50,610 versus $46,239 for females. The per capita income for the CDP was $31,474. About 11.9% of the population was below the poverty line. In 2018, the estimated median age was 35 years, with 27% under 18 years old, 64% from 18 to 64 years old, and 9% 65 years and older. For every 100 females in all age groups, there were 88.3 males. For every 100 females age 18 and over, there were 82.6 males; for every 100 age 65 and over, there were 47.6 males. Among those aged 25 or older in 2018, 87.2% graduated from high school and 36.5% obtained a bachelor's degree or higher. 2000 census As of the census of 2000, there were 11,339 housing units at an average density of . There were 10,894 households, out of which 34.9% had children under the age of 18 living with them, 53.5% were