Silva Island (also De Silva Island) is an island in San Francisco Bay, formerly completely separated from the mainland but now mostly connected. It is in Marin County, California. Its coordinates are 37°53′15″N 122°30′54″W / 37.88750°N 122.51500°W / 37.88750; -122.51500 (Silva Island), and the United States Geological Survey gives its elevation as 79 ft (24 m).

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  USGS survey map (1:62500 scale) from 1897.
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  USGS survey map (1:24000 scale) from 1954.
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  An aerial photo taken in 2013, looking toward the east.