Bel Air South is located southwest of the center of Harford County at . It is bordered to the north by the town of Bel Air and the Bel Air North CDP. It is bordered to the south by Edgewood. From the Bel Air town limits, the boundary of the Bel Air South CDP follows:
Baltimore Pike northeast to the Bel Air town limits.
Maryland Route 24 is the main road through the CDP, leading north into Bel Air and south across I-95 at Exit 77 to Edgewood. Via I-95, Baltimore is to the southwest. According to the United States Census Bureau, the Bel Air South CDP has a total area of, of which are land and, or 0.46%, are water. The unincorporated community of Emmorton is near the geographic center of the CDP. Fountain Green is an unincorporated community in the northeast part of the CDP.
Demographics
As of the census of 2000, there were 39,711 people, 14,869 households, and 11,017 families residing in the CDP. The population density was 2,528.1 people per square mile. There were 15,267 housing units at an average density of 971.9/sq mi. The racial makeup of the CDP was 91.59% White, 4.11% African American, 0.16% Native American, 2.26% Asian, 0.04% Pacific Islander, 0.65% from other races, and 1.18% from two or more races. Hispanic or Latino of any race were 1.89% of the population. There were 14,869 households, out of which 40.5% had children under the age of 18 living with them, 62.7% were married couplesliving together, 8.4% had a female householder with no husband present, and 25.9% were non-families. 21.2% of all households were made up of individuals, and 6.9% had someone living alone who was 65 years of age or older. The average household size was 2.67 and the average family size was 3.13. In the CDP, the population was spread out, with 28.7% under the age of 18, 6.0% from 18 to 24, 34.8% from 25 to 44, 21.3% from 45 to 64, and 9.2% who were 65 years of age or older. The median age was 35 years. For every 100 females, there were 95.4 males. For every 100 females age 18 and over, there were 91.0 males. The median income for a household in the CDP was $79,623, and the median income for a family was $92,258. Males had a median income of $49,566 versus $34,263 for females. The per capita income for the CDP was $26,658. About 1.4% of families and 2.6% of the population were below the poverty line, including 1.8% of those under age 18 and 8.5% of those age 65 or over.