|Coordinates||38°08′55″N122°53′52″W / 38.14860°N 122.89787°W Coordinates: 38°08′55″N122°53′52″W / 38.14860°N 122.89787°W|
|Ocean/sea sources||Pacific Ocean|
|Basin countries||United States|
|Max. length||15 km (9.3 mi)|
|Max. width||1.6 km (0.99 mi)|
|Settlements|| Inverness |
Point Reyes Station
|Official name||Tomales Bay|
|Designated||October 21, 2002|
|Reference no.||1215 |
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 mi (24 km) long and averages nearly 1.0 mi (1.6 km) wide, effectively separating the Point Reyes Peninsula from the mainland of Marin County. It is located approximately 30 mi (48 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.  On its northern end, it opens out onto Bodega Bay, which shelters it from the direct current of the Pacific (especially the California Current). The bay is formed along a submerged portion of the San Andreas Fault.
Oyster farming is a major industry on the bay. The two largest producers are Hog Island Oyster Company and Tomales Bay Oyster Company, 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, fishing and motor boating. Watercraft may be launched on Tomales Bay from the public boat ramp at Nick's Cove, north of Marshall. The sand bar at the mouth of Tomales Bay is notoriously dangerous, with a long history of small-boat accidents.
The California Office of Environmental Health Hazard Assessment (OEHHA) has developed a safe eating advisory for fish caught here, based on levels of mercury or PCBs found in local species. 
Towns bordering Tomales Bay include Inverness, Inverness Park, Point Reyes Station, and Marshall. Additional hamlets include Nick's Cove, 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.
The area is the unceded territory of the Coast Miwok. 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). 
Francis Drake is thought to have landed in nearby Drakes Estero in 1579.  Members of the Vizcaíno Expedition found the Bay in 1603, and thinking it a river, named it Rio Grande de San Sebastian. 
Early 19th-century settlements constituted the southernmost Russian colony in North America and were spread over an area stretching from Point Arena to Tomales Bay. 
The narrow gauge North Pacific Coast Railroad from Sausalito was constructed along the east side of the bay in 1874 and extended to the Russian River until it was dismantled in 1930. 
Tomales Bay State Park was formed to preserve some of the bay shore; it opened to the public in 1952. Popular units of the park include Heart's Desire Beach and Millerton Point. 
The Ramsar Convention, signed in 1971, listed Tomales Bay as a wetland of international importance.
The Giacomini Wetland Restoration Project, completed in 2008, returned to wetland several hundred acres at the south end of the bay that had been drained for grazing during the 1940s.
The Marconi Conference Center State Historical Park preserves a small hotel built by Guglielmo Marconi in 1913 to house personnel who staffed his transpacific radio station nearby. The hotel and the associated operations building and employee cottages were built by the J.G. White Engineering Corp under contract to Marconi. RCA purchased the station from Marconi in 1920. The station was closed in 1939, though other nearby radio stations on the Point Reyes Peninsula still operate today. Synanon, a drug rehabilitation organization and cult, owned it from the early 1960s until 1980, when it was purchased by a private foundation and given to the state in 1984 to operate as a conference center.
Inverness is an unincorporated community and census-designated place (CDP) in western Marin County, California, United States. It is located on the southwest shore of Tomales Bay 3.5 miles northwest of Point Reyes Station and about 40 miles (64 km) by road northwest of San Francisco, at an elevation of 43 feet. In the 2020 census, the population was 1,379. The community was named by a Scottish landowner after Inverness in Scotland.
Point Reyes Station is a small unincorporated town in western Marin County, California, United States. Point Reyes Station is located 13 miles (21 km) south-southeast of Tomales, at an elevation of 39 feet (12 m). Point Reyes Station is located along State Route 1 and is a gateway to the Point Reyes National Seashore, an extremely popular national preserve. The Point Reyes Station census-designated place (CDP) covers the unincorporated town and adjacent development to the north, with a total population of 895 as of the 2020 census.
Point Reyes National Seashore is a 71,028-acre (287.44 km2) park preserve located on the Point Reyes Peninsula in Marin County, California. As a national seashore, it is maintained by the US National Park Service as an important nature preserve. Some existing agricultural uses are allowed to continue within the park. Clem Miller, a US Congressman from Marin County wrote and introduced the bill for the establishment of Point Reyes National Seashore in 1962 to protect the peninsula from development which was proposed at the time for the slopes above Drake's Bay. All of the park's beaches were listed as the cleanest in the state in 2010.
New Albion, also known as Nova Albion, was the name of the continental area north of Mexico claimed by Sir Francis Drake for England when he landed on the North American west coast in 1579. This claim became the justification for English charters across America to the Atlantic coast and soon influenced further national expansion projects on the continent. Drake's landing site has been identified as Drake's Cove, which is part of Point Reyes National Seashore.
Coast Miwok are an indigenous people that was the second-largest group of Miwok people. Coast Miwok inhabited the general area of modern Marin County and southern Sonoma County in Northern California, from the Golden Gate north to Duncans Point and eastward to Sonoma Creek. Coast Miwok included the Bodega Bay Miwok, or Olamentko, from authenticated Miwok villages around Bodega Bay, the Marin Miwok, or Hookooeko, and Southern Sonoma Miwok, or Lekahtewutko.
Drakes Bay is a 4 mi (6 km) wide bay named so by U.S. surveyor George Davidson in 1875 along the Point Reyes National Seashore on the coast of northern California in the United States, approximately 30 mi (50 km) northwest of San Francisco at approximately 38 degrees north latitude. The bay is approximately 8 mi (13 km) wide. It is formed on the lee side of the coastal current by Point Reyes. The bay is named after Sir Francis Drake and has long been considered Drake's most likely landing spot on the west coast of North America during his circumnavigation of the world by sea in 1579. An alternative name for this bay is Puerto De Los Reyes.
Drakes Estero is an expansive estuary in the Point Reyes National Seashore of Marin County on the Pacific coast of northern California in the United States, approximately 25 miles (40 km) northwest of San Francisco.
Point Reyes is a prominent cape and popular Northern California tourist destination on the Pacific coast. Located in Marin County, it is approximately 30 miles (50 km) west-northwest of San Francisco. The term is often applied to the Point Reyes Peninsula, the region bounded by Tomales Bay on the northeast and Bolinas Lagoon on the southeast. The headland is protected as part of Point Reyes National Seashore.
Bodega Bay is a shallow, rocky inlet of the Pacific Ocean on the coast of northern California in the United States. It is approximately 5 mi (8 km) across and is located approximately 40 mi (60 km) northwest of San Francisco and 20 mi (32 km) west of Santa Rosa. The bay straddles the boundary between Sonoma County to the north and Marin County to the south. The bay is a marine habitat used for navigation, recreation, and commercial and sport fishing.
The Golden Gate Biosphere Network is an internationally recognized voluntary coalition of federal, state, and local government agencies, nonprofit organizations, universities, and private partners within the Golden Gate Biosphere (GGB) region. The Network works towards protecting the biosphere region’s biodiversity and conserving its natural resources to maintain the quality of life for people within the region. The Network has been part of the UNESCO Man and Biosphere Programme since 1988 and is part of the US Biosphere Network and EuroMAB. It is recognized by UNESCO due to the significant biodiversity of the region, as well as the Network's efforts to demonstrate and promote a balanced relationship between humans and the biosphere.
The North Pacific Coast Railroad (NPC) was a common carrier 3 ft narrow-gauge steam railroad begun in 1874 and sold in 1902 to new owners who renamed it the North Shore Railroad (California) (NSR) and which rebuilt the southern section into a standard-gauge electric railway.
Tomales Bay State Park is a California state park in Marin County, California. It consists of approximately 2,000 acres (8 km²) divided between two areas, one on the west side of Tomales Bay and the other on the east side. The main area, on the west, is part of the Point Reyes peninsula, and adjacent to Point Reyes National Seashore, which is operated by the U.S. National Park Service. The park is approximately 40 miles (64 km) north of San Francisco.
Inverness Park is a small unincorporated community in Marin County, California. It is located 1 mile (1.6 km) west-southwest of Point Reyes Station, at an elevation of 148 feet.
The Phillip Burton Wilderness is part of the 111 sq. mile (288 km2) Point Reyes National Seashore located about 20 miles (32 km) northeast of San Francisco, California. Total wilderness land is 33,373 acres which includes a roadless "potential wilderness" area of over 8,000 acres (32 km2) and is one of only three designated wilderness along the California coast, the others being the King Range Wilderness and the Rocks and Islands Wilderness. The National Park Service manages the wilderness.
L. Martin Griffin, widely known as Marty Griffin, is an American environmentalist and conservationist in Northern California and author of the book Saving the Marin–Sonoma Coast. He has also been a doctor, director of the Sonoma Developmental Center, head of the Marin Audubon Society, board member of the Marin Municipal Water District, and owner of Hop Kiln Winery in Sonoma County.
Nick's Cove is the site of a long-standing restaurant and resort in Marin County, California. It is on the northeast shore of Tomales Bay 3.25 miles (5.2 km) south-southwest of Tomales, at an elevation of 7 feet. Hog Island is in the middle of Tomales Bay, to the west of Nick's Cove, and Point Reyes National Seashore constitutes the western landmass on the opposite side of the bay.
Estero de Limantour State Marine Reserve (SMR) and Drakes Estero State Marine Conservation Area (SMCA) are two adjoining marine protected areas along the Point Reyes National Seashore in Marin County on California’s north central coast. These marine protected areas cover a combined 4.04 square miles (10.5 km2), with 1.49 square miles (3.9 km2) in the SMR and 2.55 square miles (6.6 km2) in the SMCA. Drakes Estero SMCA prohibits the take of all living marine resources from Drakes Estero except the recreational take of clams and formerly the commercial aquaculture of shellfish pursuant to a disputed state water bottom lease and permit, which has been the subject of ongoing legal proceedings since 2012, when the lease was allowed to expire.
Drakes Bay Oyster Company was an oyster farm and restaurant formerly located at the shoreline and in Drakes Estero at 38°04'57.3"N 122°55'55.0"W, a bay within Point Reyes National Seashore, on the West Marin coast of Marin County, in Northern California. In 2011, the lease for the business operation was not renewed at the direction of the United States Secretary of the Interior. After a two-year court battle, the business was terminated in December 2014, and Drakes Estero was cleared of the offshore racks and onshore structures, with the work completed in 2017.
Camp Hydle also called Drakes Bay Range was a large training center during World War II, located at Drakes Bay, on what is now Point Reyes National Seashore on the coast of northern California in the United States. The camp had several training sites: Camp Hydle, Drakes Bay Air to Ground Gunnery Range, Drakes Bay Dive Bombing Target, Camp Murphy's Ranch, Camp Hydle Maneuver Area, and Camp Hydle Skip and Dive Bombing Range. Also at the camp were landing craft training and air sea rescue training. The site was 10,532 acres of Marin County, California land on the West Coast of the United States. The complete area from Stinson Beach to the south and Dillon Beach to the north was called the Point Reyes Gunnery Range at Point Reyes. The Gunnery Range also included: two radar towers, horse stable, two lifeboat Stations, the Point Reyes Lighthouse, lookout towers, and land strafing targets (rake). The dive bomber airplanes came from Hamilton Army Airfield (AAF), Santa Rosa Army Airfield (AAF), and Naval Air Station Alameda (NAS). In addition to Drakes Bay the planes also training using the nearby Abbotts Lagoon, and Tomales Bay. The landing craft training used Limantour Beach and Limantour Spit. Anti-aircraft gun training was important training for the Pacific War. Camp Hydle base was inland 1/2 mile east of Limantour Beach. For gunner training planes towed targets across Drakes Bay. Ships also trained at the base, like the USS Walton and USS Nevada (BB-36). The Navy's Camp Hydle took over the Point Reyes Lifeboat Station during the war. The 50 men at the Station were air sea rescue pilots, dropping rafts to plane crew that landed in the ocean during training. The first troops arrived at the site on December 7, 1941. The site was also used as a coast defense spot, looking out for Japanese subs and ships. Most of the land was leased from Leland Murphy, after the war in 1962, the site became Point Reyes National Seashore.