What is today Naval Base Ventura County, was originally NAS Point Mugu, Port Hueneme and San Nicolas Island. Point Mugu began as an anti-aircraft training site, in World War Two, and was soon converted to a Navy missile test site, answering a need for a sea test site for Navy ordnance. Starting in the late 1940s NAS Point Mugu became the development and test center for several new missiles.

In the 1950s, NAS Point Mugu provided airlift support for NCBC Port Hueneme, which supplied the bulk of the Seabee support for the Navy in the Korean War. In the 1960s NAS Point Mugu was the site of the start of the Navy Marine Mammal Program, before its relocation to Point Loma. In the 1980s Point Mugu was the primary air station supporting President Reagan's travel to his California home.

Port Hueneme was for decades a primary shipment point as the Advance Base Depot, and later Naval Construction Battalion Center. A vast river of materiel flowed through NCBC Port Hueneme to the Pacific Theater of World War Two and the Korean War, and continued support through to the present.

San Nicolas Island was for many years a launching and testing site for missile development. It has also been used for developing and housing various sensing and detection equipment. It may be most famous as the Island of the Blue Dolphins, the island where a Native woman was stranded for several years, the basis for the book The Island of the Blue Dolphins by Scott O'Dell. She was eventually found and relocated to the mainland, in the mid19th Century.