Millington is a city in Shelby County, Tennessee, United States, and is a part of the Memphis metropolitan area. As of the 2010 census, it had a population of 10,176. Millington was granted the title "Flag City Tennessee" by the Tennessee State Legislature. The Naval Support Activity Mid-South is located at the former Memphis Naval Air Station, whose function was changed in 1993 from a training base to an administrative one.