Killen is a town in Lauderdale County, Alabama, United States.

[7] According to the U.S. Census Bureau, the town has a total area of 1.9 square miles (4.9 km2), all land.

There were 484 housing units at an average density of 253.0 per square mile (97.7/km2).

18.2% of households were made up of individuals, and 9.0% were one person aged 65 or older.

There were 499 housing units at an average density of 262.2 per square mile (101.2/km2).

26.9% of households were made up of individuals, and 10.7% were one person aged 65 or older.

As of the 2020 United States census, there were 1,034 people, 484 households, and 357 families residing in the town.

Killen Founder's Day is an annual event celebrated during the second weekend in August.