Colorado county map.
Colorado county map.

Weld tops Colorado’s large counties in growth

Weld County isn’t just growing — it’s setting the pace.

New U.S. Census Bureau estimates show that Weld ranks as Colorado’s fastest-growing large county, propelling it past Larimer County in population for the first time and reinforcing a regional shift that is redefining the Front Range.

The milestone builds on an earlier turning point: Weld surpassed Boulder County in population soon after the 2020 census, and has continued to widen that lead.

The latest county population estimates, released at 12:01 a.m. Eastern Time Thursday and reflecting data as of July 1, 2025, show Weld posting year-over-year population growth of 1.92%, reaching 378,426 residents — the strongest growth rate among Colorado counties with 50,000 or more residents. That growth pushed Weld past Larimer County, at 377,292 residents, and further ahead of Boulder County, at 328,560. Weld’s growth rate also exceeded that of Douglas County, long one of the state’s fastest-growing, at about 1.6%, and well above Colorado’s overall growth rate of 0.4%.

Year-over-year changes highlight diverging trends in the region. Larimer County grew about 0.82%, while Broomfield County saw a 0.98% increase. Boulder County, in contrast, declined slightly, down about 0.28%. Beyond Northern Colorado, other large counties posted mixed results: Adams County showed continued growth, Jefferson grew slightly, and Arapahoe and Denver declined.

While Weld’s one-year growth exceeded that of other large counties, its growth since the April 1, 2020, census has been even more dramatic, with Weld adding 49,445 residents — a 15% increase — making it No. 1 among large counties. Larimer County grew about 5%, and Broomfield recorded 6.84% growth over the same period. Boulder County has lost population, reflecting higher housing prices and less room to build.

Local economic and business leaders say Weld’s growth reflects both its relative affordability and its geographic reach.

“It’s continuing to be a leader in growth on the Front Range and an ideal destination,” said Rich Werner, president and CEO of Upstate Colorado Economic Development. “There’s a variety of options here — different types of communities, different price points — that allow for a range of housing and lifestyle choices.”

That diversity, Werner said, sustains a broad labor market that extends well beyond county lines. Weld’s workforce spans a roughly 45-mile radius, he said, creating what he described as distinct north and south Weld labor sheds, with the latter stretching into the Denver metro area.

Werner also pointed to a diversifying economy as a key driver. Agriculture and energy dominate the Weld County economy, but growth is also being fueled by industries including life sciences, aerospace, distribution and IT, increasing demand for skilled workers. As a result, companies are relocating Weld or expanding operations there to reach a broader labor pool.

Housing availability also plays a role, said Dennis Schick, managing broker of Re/Max Alliance.

“There’s a lot more new homes available in Weld County. The builders are building in Weld County — and when people build, people come,” Schick said. “There are more opportunities for affordable homes, so we’re seeing migration into those communities.”

Schick said growth is especially strong in Greeley — particularly west Greeley — as well as in Severance, the Weld County portion of Windsor, and southern Weld, including Frederick, Firestone, Dacono and Erie. That southern Weld growth is fueled by spillover from Boulder County and the Denver area, he said.

Nationally, population growth slowed from July 1, 2024, to July 1, 2025, in a majority of the nation’s 3,143 counties and District of Columbia, according to the Census Bureau. That’s attributed in part to lower levels of net international migration, with nine out of 10 counties experiencing drops in that category. Many large counties also are experiencing lower birth rates, as well as net domestic migration loss.

From 2024 to 2025, the fastest-growing counties in the U.S. were:

1, Jasper County, South Carolina, 6%.

2, Waller County, Texas, 5.7%.

3, Kaufman County, Texas, 5.7%.

4, Jackson County, Georgia, 5.3%.

5, Long County, Georgia, 5.2%.

6. Brunswick County, North Carolina, 4.7%.

7. Pinal County, Arizona, 4.6%.

8. Liberty County, Texas, 4.4%.

9. Dawson County, Georgia, 4.2%.

10. Caldwell County, Texas, 4.2%.

Colorado population by county, 2025
Hover or tap any county to see its 2025 population estimate and percent change since the 2020 Census base. BizWest’s four-county coverage area — Boulder, Broomfield, Larimer, and Weld — is outlined in gold.
Show: BizWest coverage area
Loading county boundaries…
← Hover or tap a county
Source: U.S. Census Bureau.
What’s driving population change in Northern Colorado?
Migration — not births — is the primary engine of population growth in Weld and Larimer counties. Boulder County is losing residents to domestic out-migration faster than births can replace them.
Boulder — net change
−925
Dom. out-mig: −2,248
Broomfield — net change
+771
Dom. net mig: +286
Larimer — net change
+3,092
Dom. net mig: +2,050
Weld — net change
+7,146
Dom. net mig: +3,857
Source: U.S. Census Bureau.
Colorado’s fastest- and slowest-growing counties since 2020
Weld County’s 15% growth since the 2020 Census base ranks it among the state’s fastest-growing, while Boulder County joins Jefferson as one of only two large counties to lose population.
Weld County (BizWest)
+15.0%
+49,445 people · #1 fastest
Larimer County (BizWest)
+5.1%
+18,223 people · #7 fastest
Broomfield County (BizWest)
+6.8%
+5,071 people · tied #5
Colorado state
+4.1%
+237,235 people statewide
Source: U.S. Census Bureau.
Weld ranks No. 1 for growth among large counties
Of Colorado’s 16 counties with at least 50,000 residents, Weld grew the fastest from 2020 to 2025 at 15%, while Boulder and Jefferson were the only two to lose population.
Weld County — #1
+15.0%
+49,445 residents
Broomfield County — #4
+6.8%
+5,071 residents
Larimer County — #5
+5.1%
+18,223 residents
Boulder County — #15
−0.7%
−2,201 residents
Source: U.S. Census Bureau.
Weld County edges past Larimer in population
Weld County overtook Larimer County in 2025 to become the most populous county in BizWest’s coverage area, surpassing it by just 1,134 residents after closing a gap of more than 30,000 since 2020. Weld has also widened its lead over Boulder County, which has lost population since 2020.
Colorado total
6.01M
+4.1% since 2020 base
Largest county
El Paso
757,040 (+3.5%)
Weld County
378,426
+15.0% — fastest large-county growth
Boulder County
328,560
−0.7% — only large county declining
Source: U.S. Census Bureau.
Weld County’s population surges while Boulder stagnates
New U.S. Census Bureau estimates show that Weld County added nearly 50,000 residents between 2020 and 2025 — the largest numeric gain in BizWest’s coverage area — while Boulder County shed population over the same period.
Boulder County −0.7%
328,560
−2,201 residents since 2020
<
Broomfield County +6.8%
79,174
+5,071 residents since 2020
<
Larimer County +5.1%
377,292
+18,223 residents since 2020
<
Weld County +15.0%
378,426
+49,445 residents since 2020
<
Source: U.S. Census Bureau.
15 years of population change in BizWest’s four-county region
Weld County has added more than 125,000 residents since the 2010 census — nearly doubling in size — while Boulder County’s rapid growth of the early 2010s stalled after 2017 and reversed during the pandemic.
Boulder County +11.5% since 2010
328,560
294,567 in Apr 2010 · +33,993 total
<
Broomfield County +41.6% since 2010
79,174
55,889 in Apr 2010 · +23,285 total
<
Larimer County +25.9% since 2010
377,292
299,630 in Apr 2010 · +77,662 total
<
Weld County +49.6% since 2010
378,426
252,825 in Apr 2010 · +125,601 total
<
Vertical dashed line marks the series break between the 2010–2020 intercensal estimates and the 2020–2025 postcensal estimates.
Source: U.S. Census Bureau.