Redstone Arsenal (RSA) is a United States Army post and a census-designated place (CDP) adjacent to Huntsville in Madison County, Alabama, United States and is part of the Huntsville-Decatur Combined Statistical Area. The Arsenal is a garrison for a number of tenants including the United States Army Materiel Command, Army's Aviation and Missile Command, the Missile Defense Agency of the Department of Defense, and NASA's Marshall Space Flight Center. Many of these units are moving due to decisions by the Defense Base Realignment and Closure Commission. The Redstone Arsenal CDP had a population of 1,946 as of the 2010 census.