SALT LAKE CITY — Utah County is Utah's fastest growing county no matter what source of data you use.

The state's second-largest county is believed to have gained 21,875 people from July 1, 2023, to July 1, 2024, according to new county population estimates released by the U.S. Census Bureau on Thursday. That made it the nation's 30th-fastest growing U.S. county in a list led by some of the country's heaviest hitters that rebounded from COVID-19, the agency noted.

Utah County's gains were propelled by the fast-growing Provo-Orem-Lehi metropolitan area, which grew by 3%, tying Daphne-Fairhope-Foley, Alabama, as the fifth-fastest growing metropolitan area in terms of percentage growth.

How Utah compares to the U.S.

Thursday's data dump gives greater clarity to the statewide data the U.S. Census Bureau released in December. Utah tied for third in percentage growth between mid-2023 and mid-2024, while the country overall had its largest population leap in over two decades.

Utah County continues to lead Utah's population growth, a point previously brought up by the Utah Population Committee at the University of Utah Kem C. Gardner Policy Institute, which released its countywide data last month. The two use different birth, death, housing and other types of datasets to project population changes during the same time frames.

State lawmakers recently passed a bill this year to rely more on the Policy Institute for state decisions moving forward, finding that the committee captures growth sooner than the federal government. However, the data released on Thursday still gives a snapshot of how localized growth compares with other U.S. counties.

The bureau found Salt Lake County's growth was second in Utah and 41st overall in the U.S. Both Salt Lake and Utah counties even topped several states in numeric growth last year.

Washington, Davis and Weber counties rounded out the top five in Utah, but no other county in the state landed in the U.S. Top 100. None of Utah's counties landed in the top 10 in percentage growth, either. The bureau found that Wayne, Piute, Grand and Daggett counties all lost residents last year, some of which were noted in the committee report.

Provo-Orem-Lehi was Utah's only metropolitan or micropolitan area that landed in the top 10 of any growth categories.

The South and West continued to dominate in growth last year, according to the data. Harris County, Texas, led the nation in numeric growth, adding close to 106,000 residents over the past year. Its gains were over 40,000 more than Miami-Dade County, Florida, which was second. Maricopa County, Arizona; Collin County, Texas; and Clark County, Nevada, rounded out the top five.

Dawson County, Georgia, led all counties with at least 20,000 residents in percentage growth. Its population jumped by 6.4%.

Interestingly enough, counties in the South and West also topped the list in both numeric and percentage declines. Five Mississippi counties landed in the Top 10 in percentage decline, led by Yazoo County's 6.4% decrease — losing about 1,600 residents in a year. Shelby County, Tennessee, had the largest numeric decline after losing nearly 3,400 residents.

What's driving growth?

Census Bureau data doesn't explain why some counties grow faster than others, or why some decline.

That said, federal demographers explained in December that they were able to obtain new data sources that helped them improve their methodology. They found there had been a rise in international migration, which was fueled by the end of pandemic-era travel restrictions and a spike in humanitarian migrants in 2023 and 2024.

Related:

Is Utah's growth stabilizing? Not in some counties

State growth slowed down some, but its population still surpassed 3.5 million in 2024, according to a new state population report.

Kristie Wilder, a demographer in the Census Bureau's population division, said Thursday that all 387 of the nation's metro areas experienced international migration increases between mid-2023 and mid-2024, showcasing major cities attracted growth from all over the world.

"Increasingly, population growth in metro areas is being shaped by international migration," she said in a statement. "While births continue to contribute to overall growth, rising net international migration is offsetting the ongoing net domestic outmigration we see in many of these areas."

Census data shows Miami-Dade County, Florida and Harris County, Texas, also led all counties in international migration, gaining 224,961 international residents combined. Los Angeles County, California; Cook County, Illinois; and Broward County, Florida, rounded out the top five in this category.

Salt Lake County led Utah in international migration with nearly 19,000 residents added — the 29th highest in the nation. Salt Lake County was also 29th in new births, leading the state in that category too, both of which helped offset population losses in other categories.

Montgomery County, Texas, drew in 23,919 new residents from other U.S. locations, nudging Pinal County, Arizona, to lead the nation in domestic migration. Pasco County, Florida; Polk County, Florida; and Collin County, Texas rounded out the top five.

Utah County attracted a little over 5,000 domestic migrants in 2024 to lead all Utah counties. Its total was 49th-highest among U.S. counties in this category, while its number of births was second to Salt Lake County in the state and 43rd overall.

Natalie Gochnour, director at the Gardner Policy Institute, said last month that housing affordability was also a potential factor in growth, adding that the Utah Population Committee believes it's "moderating our growth."

"That's just one of a few (factors), but that's certainly a significant one," she said at the time. I'll also add there's incredible uncertainty in the economy right now, and when you're uncertain you don't invest or you don't hire."

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