The 673d Air Base Wing is the support unit for Joint Base Elmendorf-Richardson, a combination of the United States Air Force's Elmendorf Air Force Base and the United States Army's Fort Richardson. The 2005 Base Realignment and Closure Commission called for the combination of the two installations. The wing replaced the 673d Air Base Wing (Provisional), which had been formed in January 2009, primarily from elements of the 3d Mission Support Group.