Sea Ranch (also known as The Sea Ranch) is an unincorporated community in Sonoma County, California, United States that was developed as a planned community beginning in the 1960s. It is known for its distinctive timber-frame structures designed by several noted American architects. The first unit built at Sea Ranch, Condominium One, was placed on the National Register of Historic Places in 2005. The community's ten-mile development played a role in the establishment of the California Coastal Commission. The population was 1,169 at the 2020 census. For statistical purposes, the United States Census Bureau has defined Sea Ranch as a census-designated place (CDP).

The first people known to live in the area were Pomos, who gathered kelp and shellfish from the beaches.

In 1846, Ernest Rufus received the Rancho German Mexican land grant, which extended along the coastline from the Gualala River to Ocean Cove. The land was later divided. In the early 1900s, Walter P. Frick bought up the pieces to create Del Mar Ranch, which was leased out for raising sheep. In 1941, the land was sold to Margaret Ohlson and her family.

Architect and planner Al Boeke envisioned a community that would preserve the area's natural beauty. Boeke first surveyed the land in 1962. In 1963, Oceanic California Inc., a division of Castle and Cooke Inc., purchased the land from the Ohlsons and assembled a design team. A progressive residential community was envisioned that would be built in a way that was not only in tune with nature, but driven by nature. Principal designers who were recruited by Boeke included American architects Charles Moore, Joseph Esherick, William Turnbull Jr., Donlyn Lyndon, Richard Whitaker, and landscape architect Lawrence Halprin. Halprin created the master plan for Sea Ranch, which encompass 10 miles (16 km) of the Sonoma County coastline. The principal photographer for the project was the architectural photographer Morley Baer, a friend and colleague of both Turnbull and Halprin. Marion Conrad was hired to manage the public relations for The Sea Ranch. The logo for The Sea Ranch was designed by Barbara Stauffacher Solomon along with her Supergraphics used throughout the development and its publications and documents.

While the County Board of Supervisors initially regarded the developer's offer to dedicate 140 acres (0.57 km) for public parkland as sufficient, opponents felt more coastal access was necessary. The site, containing ten miles (16 km) of shore, had been available to the public, but would be reserved for private use under the developer's plan. Areas below the high tide line were and would remain public property, but the plan provided no access through the development. In addition, California's coast at the time was only open to the public along 100 of its 1,300 miles (2,100 km).

Californians Organized to Acquire Access to State Tidelands (COAST) was formed in response to this issue, and their 1968 county ballot initiative attempted to require the development to include public trails to the tidelands. While the initiative did not pass, the California legislature's Dunlap Act did pass that year and required that new coastal development dedicate trails granting public access to the ocean. This episode led to the establishment of the Coastal Alliance, an organization of 100 groups similar to COAST, that placed Proposition 20 on the statewide 1972 ballot. The initiative passed, and it established the California Coastal Commission that continues to regulate land use on the California coast.

The Sea Ranch is located along the Pacific Coast, about 100 mi (160 km) north of San Francisco and 120 mi (190 km) west of Sacramento. The Sea Ranch is reached by way of State Route 1.

Approximately 4 mi (6 km) northwest of The Sea Ranch, in neighboring Mendocino County, is Gualala, a small town.

According to the Köppen Climate Classification system, Sea Ranch has a warm-summer Mediterranean climate, abbreviated as "Csb" on climate maps.

The public media station KGUA which is located imidealely north of Sea Ranch in Gualala, CA, broadcasts localy on 88.3 FM  and provides local media coverage of Sea Ranch events.

The The Independent Coast Observer Community News is a weekly newspaper which publishes news and information about the local areas of Mendocino and Sonoma counties. Coloquialy referred to as "the mendonoma coast."

Historical population

Census	Pop.	Note	%±
1980	307		—
1990	526		71.3%
2000	751		42.8%
2010	1,305		73.8%
2020	1,413		8.3%
U.S. Decennial Census

For statistical purposes, the United States Census Bureau has defined Sea Ranch as a census-designated place (CDP). The census definition of the area may not precisely correspond to the local understanding of the community.

The 2020 United States Census reported that The Sea Ranch had a population of 1,169. It was reported That the population density was 72.2 inhabitants per square mile (27.9/km). The racial makeup of The Sea Ranch was 1,012 (86.7%) White, 5 (0.3%) African American, 5 (0.3%) Native American, 19 (1.7%) Asian, 0 (0.0%) Pacific Islander, 37 (2.8%) from other races, and 93 (11.4%) from two or more races.

There were 583 households, out of which 62 (7.2%) had children under the age of 18 living in the households.

There were 1,781 housing units at an average density of 108.1 per square mile (41.7/km), of which 88.5% were owner-occupied and 11.5% were occupied by renters. The homeowner vacancy rate was 3.6%; the rental vacancy rate was 38.6%.

The 2010 United States Census reported that The Sea Ranch had a population of 1,305. The population density was 80.7 inhabitants per square mile (31.2/km). The racial makeup of The Sea Ranch was 1,220 (93.5%) White, 15 (1.1%) African American, 3 (0.2%) Native American, 10 (0.8%) Asian, 0 (0.0%) Pacific Islander, 37 (2.8%) from other races, and 20 (1.5%) from two or more races. Hispanic or Latino of any race were 117 persons (9.0%).

The census reported that 100% of the population lived in households.

There were 689 households, out of which 58 (8.4%) had children under the age of 18 living in them, 407 (59.1%) were opposite-sex married couples living together, 19 (2.8%) had a female householder with no husband present, 9 (1.3%) had a male householder with no wife present. There were 27 (3.9%) unmarried opposite-sex partnerships, and 21 (3.0%) same-sex married couples or partnerships. 197 households (28.6%) were made up of individuals, and 113 (16.4%) had someone living alone who was 65 years of age or older. The average household size was 1.89. There were 435 families (63.1% of all households); the average family size was 2.25.

The population was spread out, with 105 people (8.0%) under the age of 18, 18 people (1.4%) aged 18 to 24, 92 people (7.0%) aged 25 to 44, 495 people (37.9%) aged 45 to 64, and 595 people (45.6%) who were 65 years of age or older. The median age was 63.7 years. For every 100 females, there were 91.6 males. For every 100 females age 18 and over, there were 90.2 males.

There were 1,818 housing units at an average density of 112.4 per square mile (43.4/km), of which 85.8% were owner-occupied and 14.2% were occupied by renters. The homeowner vacancy rate was 3.4%; the rental vacancy rate was 38.8%. 81.5% of the population lived in owner-occupied housing units and 18.5% lived in rental housing units.

In 2000, of the residents in the census tabulation, 365 (48.6%) were male and 386 (51.4%) were female. The median age was 61.3 years. Nine residents (1.2%) were aged under five years, 713 residents (94.9%) were aged 18 years or more, and 287 (12.4%) were aged 65 years or more. The census categorized 732 (97.5%) as white, 8 (1.1%) as black or African American, 2 (0.3%) as Asian, and 9 (1.2%) as two or more races. The census counted 13 residents as Hispanic or Latino. The average household size was 1.88, and the average family size was 2.17. The census counted 1,211 housing units, 365 of them owner-occupied, 35 renter-occupied, and 811 (67%) vacant. The median reported household income was $69,327, and the median per capita income was $21,587. There were 25 people (3.3%) living below the poverty line.

The Sea Ranch has distinctive architecture consisting of simple timber-frame structures clad in wooden siding or shingles. The building typology of the Sea Ranch draws on the local agricultural buildings for inspiration, in the way that those buildings are designed to deal with prevailing weather and topography. Originally, the Sea Ranch had local lumber mills to draw on for the Douglas Fir and Redwood used in the homes. The majority of the 1800 or so homes are smaller second homes, although there are approximately 300 full-time residents. Approximately half the homes are rented as weekend rentals. The eventual build-out is expected to comprise approximately 2400 homes; the number varies as some current owners purchase adjacent vacant lots and merge the two, to preserve open space. The buildings could be considered a hybrid of modern and vernacular architecture, also known as the "Third Bay Tradition" and also referred to as "Sea Ranch" style.

The original design guidelines suggest that buildings have a site-specific relationship with the landscape. The Sea Ranch design review requirements specify that the buildings become part of the landscape, not subordinate to it, but do not dominate either. Details such as exteriors of unpainted wood or muted stains, a lack of overhanging eaves, and baffles on exterior lighting subdue the appearance of the buildings in the landscape. The baffles minimize nighttime light pollution; there are no street lights to obscure the night sky. The lack of roof overhangs is also intended to allow the near-constant strong breezes to pass over the buildings without the turbulence overhangs would create. The Sea Ranch design review process does not affect the building interiors, but all construction is subject to Sonoma County Permit and Resource Management oversight.

Landscaping in The Sea Ranch is regulated by a design manual that prohibits perimeter fences and limits non-indigenous plants to screened courtyards. A herd of sheep is used to keep grass low to the ground to reduce the threat of fire during the summer months.

Over the decades many architects have designed houses at Sea Ranch, including:

• David Alpert
• Al Boeke
• J. Carson Bowler
• Obie Bowman
• Steve Brodie
• William Scott Ellsworth
• Joseph Esherick
• Nicholas Forell
• John Halley
• Paul Lucas Hamilton
• Robert Hartstock
• George W. Homsey
• James Hubbell (artist)
• Donald Jacobs
• Daniel Levin
• Donlyn Lyndon
• Louis McLane
• Charles Moore
• Fiona O'Neill
• John Ruble
• Lisa Scott
• Ted Smith
• William Turnbull Jr.
• Dimitri Vedensky
• Ned Westover
• Richard Whitaker
• Buzz Yudell

• Barbara Stauffacher Solomon

• Lawrence Halprin

Condominium One (completed in 1965) was awarded the American Institute of Architects Twenty-five Year Award in 1991, and was added to The National Register of Historic Places in 2005.

Sea Ranch Chapel.

The Sonoma County Regional Parks Department provides coastal access from six places along State Route 1 in The Sea Ranch area:

• Black Point (trail) at 35035 State Route 1
• Gualala Point Regional Park at 42401 State Route 1
• Pebble Beach (trail) at 36448 State Route 1
• Shell Beach (trail) at 39200 State Route 1
• Stengel Beach (trail) at 37900 State Route 1 (closed)
• Walk On Beach (trail) at 40101 State Route 1

• The Sea Ranch Association
• History of The Sea Ranch Area
• Aerial photographs of The Sea Ranch
• Journey to The Sea Ranch
• SFMOMA-Exhibition "The Sea Ranch, Architecture, Environment, and Idealism", December 22, 2018 to April 28, 2019 including video of the founding participants of the development