loading . . . Colorado’s State Demography Office Summarizes County Level U.S. Census Data Released Today Media Contact:
Kelly May | [email protected] | (303)-656-7464
New county-level estimates from the U.S. Census Bureau, summarized by the Colorado State Demography Office, provide detailed insight into the state’s changing population trends through July 1, 2025.
The population estimates published today are the Census Bureau's official figures for the years between the decennial censuses.
Colorado is still experiencing positive overall population growth statewide (0.4% or 24,059 people). This latest data reflects the strongest positive net migration to Douglas, Larimer, and Weld counties, areas that have seen some of the largest increases in residential construction.
However, the new county data shows that some counties lost populations to other states or counties. These counties included:
Several high housing cost counties.
Those counties that received the highest numbers of international migrants in preceding years (July 2021 to July 2024). A portion of these recent international migrants likely moved to other states or counties in 2025, resulting in net negative domestic migration.
Under the Census Bureau’s count, when a person moves from a foreign country to the U.S., they are counted as an international migrant. However, if they move to another state in the following year, they are then counted as domestic migrants.
Key Takeaways
County Growth Leaders (July 2024 to July 2025)
Largest Numeric Population Increases: Weld County saw the largest change, gaining 7,146 residents (1.9%), followed by Douglas County (+6,345 or 1.6%), Adams County (+5,411 or 1.0%), El Paso County (+4,684 or 0.6%), and Larimer County (+3,092 or 0.8%).
Fastest Rates of Growth: Elbert County had the fastest growth rate at 4.1% (+1,190 people), followed by Gilpin County (2.0% / +118), Weld County (1.9% / +7,146), Ouray County (1.8% / +92), and Douglas County (1.6% / +6,345).
Outflow and Inflow Summaries
Concentrated Net Negative Migration: Arapahoe and Denver Counties together accounted for nearly 18,000 in domestic net negative migration (more outs than ins) between July 2024 and July 2025. Boulder and Jefferson Counties show similar patterns of net negative migration in 2025 but at smaller levels.
Several higher housing cost counties along the Western slope also experienced net negative domestic migration, including Eagle, Pitkin, and Summit Counties.
Largest Domestic Inflow: Weld, Douglas, Larimer, Mesa, and Elbert Counties had the largest net positive domestic (state-to-state or county-to-county) migration.
Largest International Inflow: Arapahoe, Denver, Adams, Jefferson, and Boulder Counties continued to have the largest net international migration in 2025, though at much lower levels than 2024.
Natural Change
Natural Increase Leaders: Denver, El Paso, Adams, Arapahoe, and Weld Counties recorded the highest natural increase (more births than deaths), maintaining the same ranking as the previous year.
Natural Decline: Thirty-three counties experienced natural decline (more deaths than births), with the largest volumes recorded in Mesa County and Pueblo County.
Longer-Term Trends
Post-2020 Declines: Since the 2020 Census, 24 counties have experienced a population decline as of July 1, 2025. The largest losses since 2020 were recorded in Jefferson County, Boulder County, and Eagle County.
Fewer Movers: Reasons for the reduced net migration reflect national trends in slower job growth, relative housing affordability, changes in immigration policy, and fewer people moving due to higher interest rates and aging in place.
Secondary Migration: At least some portion of the domestic out-migration is made up of recently arrived international migrants (arriving between 2022 and 2024) who have moved to other states as Colorado was not their intended final destination.
The State Demography Office incorporates information from these estimates into their annual population estimates, which will be published in late October 2026. The Census Bureau Vintage 2025 municipal estimates will be published in May 2026. https://cdola.colorado.gov/press-release/colorados-state-demography-office-summarizes-county-level-us-census-data-released?utm_source=censusSDC
