Deer Island is a former island in Marin County, California, close to the Novato Creek, upstream of San Pablo Bay. It is now the location of Deer Island Preserve. It used to be inhabited by Antonio DeBorba, who hiked the nearby wetlands to avoid having to use a boat to get home. The building is still there on the Northeastern part of the island. Deer Island's coordinates are 38°05′52″N 122°32′13″W, and its elevation is 167 ft (51 m).