California's population grew by almost 300,000 last year to nearly 38 million people, with the San Francisco Bay Area leading the growth, the state Department of Finance reported Wednesday.
Four of the five fastest-growing counties and several of the state's fastest-growing cities are in the Bay area, according to the annual report.
Santa Clarita in Los Angeles County was the fastest-growing city last year after annexing several other communities.
It was followed by Dublin in Alameda County, Lake Elsinore in Riverside County, Imperial in Imperial County and Indio in Riverside County.
The fastest-growing counties were Santa Clara, Alameda, Yuba, San Mateo and San Francisco.
Los Angeles remains the state's largest city, with a population of nearly 3.9 million, followed by San Diego, with 1.3 million, and San Jose, now at more than 984,000.
California's total population was more than 37.9 million.
While most cities gained population in 2012, 37 saw their populations decline. Among the largest drops were cities that previously had large prison populations, such as Calipatria in Imperial County, which saw an 11 percent population decline, and Ione in Amador County, which dropped by 5.9 percent.
Even Folsom, in Sacramento County, which typically adds population, fell by 0.5 percent last year as part of the state's move to cut the overall prison population and shift some lower-level offenders to county-run programs.
Folsom is home to two state prisons. California's housing market remains at historically low levels but was up 27 percent over 2011, adding more than 45,000 new housing units, the report found.
Several of the fastest-growing cities added large numbers of additional housing.
The state compiles the annual populations of California cities to calculate their estimated share of state funding for various programs.
Separately, the state has forecast that Hispanics will equal the number of whites in California by the middle of this year and surpass them in early 2014.
Whites and Hispanics each represent about 39 percent of the state's population.