Newly released data from the U.S. Census Bureau shows the Pittsburgh region’s population shrank slightly recently.
The data includes population estimates for American counties from July 2024 to 2025.
All but three counties in the eight-county Pittsburgh metropolitan statistical area saw a decline in population, according to a dataset compiled by University of Pittsburgh regional economist Chris Briem.
Allegheny County, home to 1.2 million people, saw a decline of .17%, losing about 2,100 residents.
Westmoreland County, the region’s second most populous, lost .33% of its residents, dropping just below 350,000 people.
Beaver, Butler and Washington counties all saw slight population gains. Butler, which saw the highest increase, gained 1,200 new residents, a .44% gain.
Armstrong County remained about steady at 63,700 residents.
In total, the metro area shed about 3,100 residents, a decline of .13%.
That’s mostly because the region saw more deaths than births, a trend that dates to the 1990s, according to Briem’s report.
Among the 40 largest metros in the country, Pittsburgh had the worst birth-to-death ratio. The only other major metros in the top 40 that saw more deaths than births were Cleveland; Tampa, Fla.; St. Louis; and Providence, R.I.
Domestic migration, or those moving from elsewhere in the U.S., was up in every county but Allegheny, which saw more than 2,700 residents move away last year.
That figure was nearly canceled out in the county by international migration, however. Almost 2,500 people moved to the Allegheny County from abroad.
[Source: U.S. Census Bureau]
Nationally, growth slowed in about 90% of counties compared to the prior year, according to a U.S. Census Bureau release.
“These shifts were largely due to lower levels of net international migration, which declined nationwide,” the release said.
The metros that drew the highest numbers of new residents include Houston, Dallas, Atlanta and Phoenix.
Los Angeles County, which shed nearly 54,000 people, remains far and away the nation’s most populous county with almost 9.7 million residents.