The base's diverse geography, spanning over , plays host to year-round training for Marines in addition to all other branches of the U.S. military. Amphibious and sea-to-shore training takes place at several key points along the base's of coastline. The main base is in the Mainside Complex, at the southeastern end of the base, and the remote northern interior is an impact area. Daytime population is around 100,000. Recruits from nearby Marine Corps Recruit Depot, San Diego spend four weeks at Pendleton's Edson Range receiving field training; after graduating from recruit training, newly-minted Marines return to the base's School of Infantry for further training.