The San Jose Public Library serves more Bay Area residents – 1,049,187 million – than any other library in the region, according to the California State Library.

Contra Costa County is right behind San Jose, as the only other library system in the region serving more than a million residents (1,042,344 million).  

On June 1, at the beginning of each fiscal year, the state librarian is required to determine how many people are being served by California’s 1,128 public libraries in 186 jurisdictions. Those numbers reflect census data compiled by the U.S. Department of Commerce or estimates prepared by California’s Department of Finance, whichever is most current. 

The most recent results are for Jan. 1, 2020, were certified June 1, and updated in August.  

Only a small fraction of California’s 39,782,870 residents weren’t represented by either a county or city library (about 15,000 people in unincorporated Lassen County and Los Angeles County’s City of Industry weren’t technically being served by a California public library). 

The state’s largest system is Los Angeles (4,010,684 people), followed by Los Angeles County (3,351,753). Sacramento is the largest system in Northern California (1,473,755). 

Most jurisdictions – whether city or county – have multiple branches. 

There is no similar state system, per se, though the state library was founded in 1850 and has physical libraries in Sacramento and San Francisco. The state library’s purpose is to consult, provide technical assistance and direct state and federal funding to public libraries within the state. 

Even California librarians say jurisdictional lines sometimes get confusing.  

“Regarding why there are so many library jurisdictions in California, I don’t have a clue, except perhaps that many cities started their own library systems years ago and decided to keep things as local as possible,” said James Moore, the city librarian for San Mateo. “There are two San Mateo library systems that people often confuse. One is us, the city, and the other is the (San Mateo) county system. County services a lot of smaller cities and jurisdictions that are quite spread out and sometimes rural.” 

The Bay Area has 38 separate public library jurisdictions. 

Following San Jose and Contra Costa, the ones serving the most people include San Francisco (897,806), Stockton-San Joaquin County (705,702), Alameda County (589,928), Sonoma County (492,980), Oakland (457,448), Santa Clara County (444,238), Solano County (389,856), and San Mateo County (284,138). 

The smallest systems are in St, Helena (6,073) and Sausalito (7,252).