PHOENIX – For some it’s the weather, others are chasing lower home prices or relocating for better job opportunities. These are among the factors that made Maricopa County the fastest-growing county in the nation last year.

Maricopa County added 56,831 residents between July 2021 and June 2022, the largest population growth for a county in the nation, according to the U.S. Census Bureau, which said the county had an estimated 4.5 million residents last year. It was the second straight year the county led the nation in population growth. Maricopa added 46,866 people in 2021.

“It’s a beautiful valley, not susceptible to too many natural disasters, not in a tornado zone or an earthquake zone,” said Clint Hickman, chairman of the Maricopa County Board of Supervisors. “I think (the population growth) is driven by the opportunity to start a new life in a fantastic climate.”

Census Bureau data showed most of the population increase came from domestic migration, or people moving into the county from other places in the United States.

Of the 56,831 new residents of Maricopa County, only 7,806 were attributed to natural change, which is the difference between births and deaths. The rest were domestic or international migrants.

Many new residents are still coming from California, according to Scott Wilken, data advisory program manager for the Maricopa Association of Governments.

“We’re seeing more households coming from California than any other single state,” Wilken said. “The latest data shows that between 20% and 25% of people moving to the Phoenix metro area have come from California. That’s an incredible amount just from one state alone.”

There is not one place in Maricopa County experiencing significantly more growth than any other, Wilken said.

Chris Camacho, president and CEO of the Greater Phoenix Economic Council, said a rising number of younger residents are calling Maricopa County home. Many are moving here for jobs in technology, engineering and insurance, he said.

“The migration pattern of people feeds the economic development potential because we’re able to support the growth of new companies,” Camacho said.

Opportunity is an important part of the job market. Big technology and engineering companies tend to look at markets that have growth and follow it, he said. Those companies can then draw employees from the local markets they are serving while also knowing there’s a strong pipeline of people deciding to move there.

“Population trends inward are a very healthy and good thing. It drives more housing demand. It drives more consumer purchases, which leads to a broader tax base. And it leads GDP growth in a more diverse economic base because we’re able to put these new residents into the jobs that we’ve been growing and cultivating in the region,” Camacho said.

Maricopa County remained the fourth-largest county in the nation last year, after Los Angeles County, with 9.72 million residents; Cook County, Illinois, with 5.11 million; and Harris County, Texas, with 4.78 million. Los Angeles County remained No. 1 despite also seeing the biggest decline last year, when it lost 90,704 residents.

Of the 10 counties with the biggest population gains, six were in Texas and three were in Florida. Maricopa County was the only one from Arizona.

While no other Arizona county came close to Maricopa’s numeric growth last year, Pinal County saw the fastest growth rate for the second year in a row. Pinal County added 16,010 people, a 3.6% growth rate that brought its total population to 464,154. Maricopa County grew at a rate of 1.3%.

Twelve of the 15 counties in the state saw population growth last year, according to the Census Bureau. The remaining three saw population declines: Greenlee County lost 75 residents, Cochise County lost 100 and Graham County’s population fell by 103.