Marin is one of the most segregated counties in the Bay Area, with an overwhelmingly white population that is exceptionally separated from people of color, according to a new study published by the Othering and Belonging Institute at the University of California, Berkeley. In West Marin, the San Geronimo Valley was singled out as highly segregated, but the issue afflicts the entire region.

“Whether seen from the regional perspective, the county level or the metropolitan level, the San Francisco Bay Area is simultaneously diverse but also notably and starkly segregated. The diversity of the region masks considerable levels of racial isolation and historical, persistent segregation,” the report states.

Despite efforts to create affordable housing, integrating white and nonwhite communities is a far-off reality. Segregation in Marin is exacerbated by strict regulations and roadblocks on where new housing can be built. Thus, a small number of clustered public housing or affordable housing communities are home to many of the people of color in Marin, while the rest of the county is overwhelmingly white. 

Two neighborhoods in Marin stand out for their segregation: the Canal area in San Rafael, which is over 65 percent Latino, and Marin City, a community with 27 percent African Americans, well above the countywide demographic of 1.7 percent. The report found that children growing up in predominantly nonwhite segregated neighborhoods in the 1980s did much worse as adults.

“These segregated residential patterns shape the life chances of its residents, who not only reside in racially segregated neighborhoods, but attend racially segregated schools and have racially differentiated access to a plethora of public and private resources as well. Racial segregation is the main instrument of racial inequality,” the researchers wrote.

The report does not describe segregation in West Marin because of the area’s low population density, but it does note the San Geronimo Valley, which is overwhelmingly white and has been since it was settled. According to the American Community Survey, 93 percent of residents there are white, compared to 79 percent countywide, and 5 percent of residents are Latino, compared to 15 percent countywide.

Owen Clapp, a valley historian, said there has been an extensive effort to keep nonwhite residents out of the region. When the Lagunitas Development Company subdivided the land in 1912, it included language in the covenants to the deeds that said houses could only be occupied by the Caucasian race. Some got more specific, explicitly banning Chinese or Black people. Up until the 1960s, some real estate agents refused to sell to nonwhite people, Mr. Clapp said.

Segregation also plays out in more subtle ways, particularly around housing. Because economics and race are closely linked, and people of color are less likely to benefit from intergenerational wealth, the dearth of affordable housing in Marin entrenches and exacerbates segregation; the average sale price of a home in Marin is well over $1 million. Supply is low, and demand is high.

“The need is so great that you don’t want to talk about the housing units needed, because that would just scare everybody off. Their eyes would glaze over,” said Joe Walsh, who helped found the San Geronimo Affordable Housing Association.

For much of its history, the San Geronimo Valley was one of the more affordable places to live because of its cheaply built summer homes. In the late ‘70s, real estate agents changed their marketing tone to help drum up sales, using flowery language and describing the place as an idyllic country retreat, Mr. Clapp said. By the ‘80s, costs were in line with the rest of the county, Mr. Clapp said. 

The challenge of building new homes in the valley highlights the hurdles to lowering housing costs and, in turn, reducing segregation. In the ‘90s, developers were aiming to build 139 homes on the ridge above the valley, called Skye Ranch, but they ran into huge opposition. The project was pared down to 10 large ranches, until the Marin County Open Space District purchased the property for conservation.

“The San Geronimo Valley is protected forever now, all of it. Nothing can wreck the vistas—no visual blight next door, no goddamned condos,” Supervisor Gary Giacomini said at the time, according to the San Francisco Chronicle.

As part of the property purchase, Marin awarded the San Geronimo Affordable Housing Association $205,000. Twenty-five years after its founding, the association finally had a funding source. Mr. Walsh envisioned building a 20-unit property to rent to low-income residents, but his dreams were quickly dashed by staunch opposition at meetings.

“It was butting your head against the wall, because you’re trying to sell something to people who don’t want it,” he remembered. “People said, ‘I’m all for affordable housing—just not this project, not here.’”

On top of the NIMBYism, building costs were significant. Only after another $1 million from the county and the Marin Community Foundation could a project move forward. A modest three-home project with six units in total was completed in 2000 on Sage Lane. Fifteen years later, the county helped the association purchase the 20-unit trailer court in Forest Knolls.

Land-use policies have a direct correlation with segregation. Single-family zoning, which is widespread in West Marin, is responsible for much of the segregation in the Bay Area, researchers found.

“The prevalence and over-abundance of this type of restrictive zoning is a direct impediment to the development of affordable housing and certain types of housing, including dense, multi-family housing, that make integration feasible and segregation more difficult to sustain. Without addressing this problem, an integration agenda is out of reach,” the report states.