Millbrook is a city in Autauga and Elmore counties in the U.S. state of Alabama. The population was 16,564 at the 2020 census, up from 14,640 in 2010. It is part of the Montgomery Metropolitan Statistical Area.

Autauga County is a county located in the central portion of the U.S. state of Alabama. As of the 2020 census the population was 58,805. Its county seat is Prattville.