[18][19] Its coordinates are 38°08′59″N 122°25′27″W / 38.14972°N 122.42417°W / 38.14972; -122.42417 (Tubbs Island)[1], and the United States Geological Survey measured its elevation as 0 ft (0 m) in 1981.
[20] Tubbs Island used to be home to a town of the same name, but now all that remains is a single outhouse visible from SR 37.
[21][22] Following the disappearance of the town, Tubbs Island was used as a gunnery range and chemical weapons testing site.
The government has since invested into multiple cleanups of the island, mainly of contaminated soil, sediment, and water.
It was previously diked agricultural land, but has since been restored to marshland by Audubon California.