Forestdale is an unincorporated community and census-designated place (CDP) in Jefferson County, Alabama, United States.

[2] According to the U.S. Census Bureau, the community has a total area of 6.9 square miles (18 km2), all land.

At the 2020 United States census, there were 10,409 people, 3,776 households and 2,484 families residing in the CDP.

There were 4,365 housing units at an average density of632 per square mile (244/km2).

25.2% of all households were made up of individuals and 9.3% had someone living alone who was 65 years of age or older.

There were 4,357 housing units at an average density of 631.4 per square mile (243.8/km2).

23.1% of all households were made up of individuals and 11.2% had someone living alone who was 65 years of age or older.