300px|right|west marin towns thumb|right|250px|tomales bay as viewed from tomales point trail tomales bay is a long narrow inlet of the pacific ocean in marin county in northern california in the united states. it is approximately 15 miles (25&nbsp;km) long and averages nearly 1.0 miles (1.6&nbsp;km) wide, effectively separating the point reyes peninsula from the mainland of marin county. it is located approximately 30 miles (48&nbsp;km) northwest of san francisco. the bay forms the eastern boundary of point reyes national seashore. tomales bay is recognized for protection by the california bays and estuaries policy.state water resources control board water quality control policy for the enclosed bays and estuaries of california (1974) state of california on its northern end it opens out onto bodega bay, which shelters it from the direct current of the pacific. the bay is formed along a submerged portion of the san andreas fault. thumb|tomales bay oysters oyster farming is a major industry on the bay. the two largest producers are tomales bay oyster co and hog island oyster co, both of which retail oysters to the public and have picnic grounds on the east shore. hillsides east of tomales bay are grazed by cows belonging to local dairies. there is also grazing land west of the bay, on farms and ranches leased from point reyes national seashore. the bay sees significant amounts of water sports including sailing, kayaking, and motorboating. of special interest is the bioluminescence that can be seen from june to november. watercraft may be launched on tomales bay from the public boat ramp at nick's cove, north of marshall. there is a $5 fee. the sand bar at the mouth of tomales bay is notoriously dangerous, with a long history of small boat accidents. towns bordering tomales bay include inverness, inverness park, point reyes station, and marshall. additional hamlets include spengers, duck cove, shallow beach, and vilicichs. dillon beach lies just to the north of the mouth of the bay, and tomales just to the east. ==history== the area was once coast miwok territory. documented villages in the area included: echa-kolum (south of marshall), sakloki (opposite tomales point), shotommo-wi (near the mouth of the estero de san antonio), and utumia (near tomales).{{cite web|url=http://www.accessgenealogy.com/native/california/miwokindianhist.htm|publisher=access genealogy|title=miwok ind
Bays_of_California Landforms_of_Marin_County,_California Landforms_of_the_San_Francisco_Bay_Area Places_with_bioluminescence Ramsar_sites_in_the_United_States West_Marin