Marine Corps Recruit Depot (commonly referred to as MCRD) San Diego is a United States Marine Corps military installation in San Diego, California. It lies between San Diego Bay and Interstate 5, adjacent to San Diego International Airport and the former Naval Training Center San Diego. MCRD San Diego's main mission is the initial training of enlisted male recruits living west of the Mississippi River. Over 21,000 recruits are trained each year. The Depot also is the home to the Marine Corps' Recruiter School and Western Recruiting Region's Drill Instructors School.