Modesto's population increased by more than 3,000 people last year, boosting its total number of residents to nearly 206,000, newly released estimates from the California Department of Finance's Demographic Research Unit show.
The city's 1.5 percent population boost was among the highest in the Northern San Joaquin Valley.
Hughson grew the most, increasing 2.8 percent to nearly 7,000 people.
Stanislaus County's population edged up less than 1 percent in 2012, primarily because births and immigration offset the large number of people moving out of the county, according to U.S. Census Bureau data released in March.
The Demographic Research Unit's estimates show Manteca's population topped 71,000 last year, as it grew by 2.3 percent.
Sonora and Angels Camp, by contrast, lost a few residents last year, continuing a long-term trend for Tuolumne and Calaveras counties.
Tuolumne, for instance, had more deaths than births, and far more people moved out than moved in. The county lost about 1.3 percent of its population from 2011 to 2012, dropping to about 54,000 residents.
California's population overall rose 0.8 percent during 2012, reaching an estimated 38 million.