U.S. Marine Corps Reserve | 1,142 followers on LinkedIn. The United States Marine Corps Forces Reserve is the headquarters command for over 35,000 Marines and Sailors stationed in Reserve Training Centers located throughout 47 U.S. states, Washington D.C., and Puerto Rico. The Marine Corps Reserve was established when Congress passed the Naval Appropriations Act of Aug. 29, 1916 and is responsible for providing trained units and qualified individuals to be mobilized for times of war, national emergencies, and operational tempo relief. The Marine Reserve team possesses capabilities across the full spectrum of military operations; from humanitarian assistance and disaster relief support to the most potent combat forces in the world.