The Marine Corps West Field Office is located in northern San Diego County aboard Marine Corps Base Camp Pendleton, CA. Marine Corps Base Camp Pendleton, the Corps’ largest West Coast expeditionary training facility, encompasses more than 125,000 acres of Southern California terrain and is home to an estimated 140,000 Marines and their family members. The Marine Corps West Field Office has a vast area of responsibility, including northern San Diego County, southern Orange County, Riverside and San Bernardino County. The Marine Corps West Field Office is also responsible for Las Vegas and Clark County, Nevada; the Texas counties of El Paso, Hudspeth, Reeves and Culbertson; and all of Arizona and New Mexico.

The Marine Corps West Field Office supports Marine Corps Installations West, the First Marine Expeditionary Force and eight bases/stations in Southwestern United States, to include Marine Corps Air Station (MCAS) Miramar, MCAS Yuma, MCB Camp Pendleton, MCAS Camp Pendleton, Marine Corps Recruit Depot San Diego, Marine Corps Air Ground Combat Center Twentynine Palms, Marine Corps Logistics Base Barstow, and Marine Corps Mountain Warfare Training Center Bridgeport.

Historically the NCIS Marine Corps West Field Office has served as a training office where newer agents could gain experience in investigating general crimes. The Field Office also actively works with the USMC in maintaining operational security for its extensive training programs, battlefield exercises, and warfighter capabilities, which incorporate the use of numerous role players. In addition, the Field Office is heavily engaged in safeguarding against compromise of the advanced Marine Corps technologies that are resident in the region.

Subordinate Offices