Day Island is an island at the mouth of the
Petaluma River in
San Pablo Bay (an embayment of
San Francisco Bay
San Francisco Bay is a large tidal estuary in the U.S. state of California, and gives its name to the San Francisco Bay Area. It is dominated by the big cities of San Francisco, San Jose, and Oakland.
San Francisco Bay drains water from a ...
).
It is part of
Marin County
Marin County is a county located in the northwestern part of the San Francisco Bay Area of the U.S. state of California. As of the 2020 census, the population was 262,231. Its county seat and largest city is San Rafael. Marin County is acros ...
,
California.
Its coordinates are , and the
United States Geological Survey measured its elevation as in 1981.
It appears on a 1951 USGS map of the area, although it appears on maps from as old as 1873.
The "1880 History of Marin County" by Alley, Bowen and Co. mentions "a man by name of Day" who "settled on an island in Novato township which has since borne his name" in 1851." To this day, there are still 2 houses on the island, both inhabited. The island is bordered by dirt and two lagoons to the west, and marshlands to the east, although it was once entirely surrounded by either marshland or water.
References
Islands of Marin County, California
Islands of Northern California
San Pablo Bay
Petaluma River
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