Mare Island (Spanish: Isla de la Yegua) is a peninsula in the United States in the city of Vallejo, California, about 23 miles (37 km) northeast of San Francisco.

In 1775, Spanish explorer Perez Ayala was the first European to land on what would become Mare Island – he named it Isla de la Plana.

Among the livestock feared lost in the wreckage was the prized white mare of General Mariano Guadalupe Vallejo, the Mexican Commandante for Northern California.

On November 6, 1850, two months after California was admitted to statehood, President Fillmore reserved Mare Island for government use.

On July 13, 1852, Sloat recommended the island[3] across the Napa River from the settlement of Vallejo, as it was "free from ocean gales and from floods and freshets."

The Navy Department acted favorably on Commodore Sloat's recommendations and Mare Island was purchased for use as a naval shipyard in July 1853 at a cost of $83,410.

The growing size and number of the country's naval fleet was making older facilities obsolete and led to increased building and refitting of shipyards nationally.

In 1872, the U.S. Public Works Department commenced construction of a 508-foot (155 m) drydock on the island, setting it on a foundation of cut granite blocks.

[citation needed] The vision of rebuilding Mare Island as a vital place where people lived and worked was a key goal in the base conversion planning process undertaken by the city of Vallejo in the early 1990s.

Finally, as with any restoration of an industrial, brownfield landscape, both city and government agencies required environmental reviews, toxic substance removal, and soil remediation.

LMI contracted the Sausalito-based SWA Group to provide a Master Development Plan for Vallejo, additional historical research and landscape architectural services.

In addition, 78% of the island was set aside for wildlife habitat and wetlands, parkland and open space, and dredge ponds.

Mare Island's Specific Plan calls for a total of 1,400 homes and condos, plus 7,000,000 square feet (650,000 m2) of commercial, retail, entertainment, and industrial space.

[10] Mare Island's residents petitioned LMI and the City of Vallejo to eliminate the dredge ponds, whose role had been to collect silt, drainage, and storm water from the Napa River and the Bay, and instead restore that acreage to wetlands.

The city and the developer agreed, and in January 2006, the land use plan was amended to add the Mare Island Shoreline Heritage Preserve.