MB, Mare Island Naval Shipyard, Vallejo, California

The MB (Military Barracks) unit at Mare Island Naval Shipyard in Vallejo, California, played a key role in supporting naval operations throughout its history. Established in the late 19th century, Mare Island became the first permanent U.S. naval installation on the West Coast, and the MB provided essential housing, training, and administrative functions for sailors and Marines stationed there. During both World Wars, the MB supported the rapid expansion of shipyard personnel, contributing to the shipyard's reputation as a crucial center for shipbuilding and repair. The MB continued its mission until the shipyard’s closure in 1996, after which the site transitioned to civilian use and historic preservation.