Aldan is a borough in Delaware County, Pennsylvania, United States. The population was 4,152 at the 2010 census.
According to the United States Census Bureau, the borough has a total area of 0.6 square miles (1.6 km2), all of it land.
As of Census 2010, the racial makeup of the borough was 76.3% White, 18.5% African American, 0.1% Native American, 2.6% Asian, 0.4% from other races, and 2.0% from two or more races. Hispanic or Latino of any race were 2.1% of the population .
As of the census of 2000, there were 4,313 people, 1,751 households, and 1,157 families residing in the borough. The population density was 7,235.4 people per square mile (2,775.4/km²). There were 1,817 housing units at an average density of 3,048.1 per square mile (1,169.2/km²). The racial makeup of the borough was 93.30% White, 4.34% African American, 0.19% Native American, 1.34% Asian, 0.12% from other races, and 0.72% from two or more races. Hispanic or Latino of any race were 0.93% of the population.