All those new housing developments dotting the East Bay hills don't lie. Alameda County is the second fastest growing county in the state, boosted by Dublin, one of the fastest growing cities in the state, according to new state population figures released Wednesday.

Other areas of the East Bay -- particularly eastern Contra Costa County -- also saw significant population gains in the annual numbers from the state Department of Finance. Antioch (106,455) surpassed Richmond by about 300 people, becoming the second largest city in the county for the first time.

Oakland, meanwhile, reached a milestone, surpassing 400,000 residents for the first time in its 162-year history.

Alameda County's significant gains are fed by Bay Area residents migrating from priced-out counties, such as San Francisco and Marin, said an East Bay analyst.

"This is kind of what we expected," said Darien Louie, executive director of the East Bay Economic Development Alliance. "A lot of it is associated with gentrification. We're seeing a population ... that can't afford to live elsewhere looking at options in the East Bay."

Alameda County's population increased 1.5 percent to 1.57 million people, while California gained 0.9 percent, an increase of 356,000 people.

"One thing we do have is space," Louie said, adding that ethnic communities have brought in large Asian populations to Alameda County. The county needs to ensure its aging housing and commercial stock get upgrades, such as broadband Internet access, to stay competitive, she said.

Dublin's growth had been slow -- practically flat in 2011 (0.4 percent) and slightly higher in 2012 (1.1 percent). But the city at the intersections of Interstates 680 and 580 took a big leap last year, rising from 49,932 to 53,462 residents, a 7.1 percent jump and the third fastest growing city in the state. The only two cities that registered higher growth -- McFarland in Kern County and Chowchilla in Madera County -- had statistics altered by fluctuating state prison populations.

"The growth of Dublin is something that has been planned and something we've embraced," said Mayor Tim Sbranti, noting the city has a one-to-one jobs-housing balance. "We've balanced between residential growth and commercial growth."

The East Bay city fills a housing niche not offered in Silicon Valley, said Abe Gupta, a Dublin councilman.

"Residents more and more want to move to an area with a balance of really good schools and some level of affordability," Gupta said. "We've put a lot of money into schools and a lot of money into a diverse housing stock."

The city has developed and redeveloped areas near its BART stop, including large swaths of new homes in the former Camp Parks military area.

"We've gotten closer and closer to the 'build-out' point, but we haven't reached it yet and we've got room to grow," Gupta said.

The East Bay's largest city, Oakland, remained the eighth most populous city in the state at 404,355, increasing 1.2 percent from the year before.

In Contra Costa County, Antioch saw a 1.1 percent increase, and is now second in size only to Concord (124,656) in the county.

Antioch Mayor Wade Harper said the news "doesn't really change the game plan" as far as the city's goals, including creating a strategic plan and creating jobs.

"Our priorities are still safety, reducing crime, economic development and having enough officers," he said. "Antioch is a diverse community and we welcome good people. Good, talented, law-abiding citizens."

Harper pointed out that Richmond, the city Antioch statistically leapt over, has roughly twice as many sworn police officers. He said he hoped the new rank could provide Antioch additional leverage in funding requests.

The Highway 4 corridor saw additional growth with Brentwood (2.6 percent), Oakley (2.1 percent) and Pittsburg (1.4 percent).

The expansion of Highway 4 and future extension of BART into Antioch are signs that the "infrastructure is in place to support" East Contra Costa's continuing growth, Harper said.

"We're in a much better position now than we had been," he said.

Overall, Contra Costa saw a 1 percent population increase to 1.09 million people.

California's statewide housing growth added almost 60,000 housing units compared to 45,000 the year before, up 31 percent. Cities reported about 31,000 new multiple-family housing units and 28,000 single-family homes in 2013, according to state data.

Staff writer Paul Burgarino contributed to this report. Contact Matthias Gafni at 925-952-5026. Follow him at Twitter.com/mgafni.