Is Boulder County, CO's population growing or shrinking?
Refreshed annually
It shrank by 925 between 2024 and 2025. Changes in population reflect birth and death rates, immigration patterns, regional shifts, and even the overall health of the economy. Boulder County, CO’s 0.28% annual decrease was primarily driven by people moving to other states.
In the decade between 2015 and 2025, Boulder County, CO’s population grew by 3.2%.
-925
population change (2024 to 2025)
-0.28%
percent change in population (2024 to 2025)
Since 2000, Boulder County, CO’s population increased 22 out of 25 years. The largest increase occurred between 2000 and 2001, when Boulder County, CO gained 7,200 residents. Its largest decline occurred between 2009 and 2010 when there were 7,200 fewer residents.
Boulder County, CO lost 925 residents between 2024 and 2025.
Annual population change, 2001–2025
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What contributes to population change in Boulder County, CO?
A county’s population is influenced by three factors:
- Natural population change: If births outnumber deaths in a given year, natural population growth is positive. If deaths exceed births, it is negative. Between 2024 and 2025 natural population change was positive in Boulder County, CO, with births exceeding deaths by 244.
- Immigration: international migration directly into or out of a county: If more people move in than move out, population change from immigration is positive. If more people move out than move in, it’s negative. Between 2024 to 2025, Boulder County, CO’s population change from immigration was positive with about 1,100 more people coming from another country directly to Boulder County, CO than leaving.
- Domestic migration, moving between counties: Between 2024 to 2025, Boulder County, CO’s population change from domestic migration was negative with about 2,200 more people moving to any other county in the US.
Between 2024 and 2025, domestic migration was the primary driver of population decline in Boulder County, CO.
Components of population change from previous year, 2011–2025
How is the US population changing?
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Methodology
USAFacts standardizes data, in areas such as time and demographics, to make it easier to understand and compare.
Page sources
USAFacts endeavors to share the most up-to-date information available. We sourced the data on this page directly from government agencies; however, the intervals at which agencies publish updated data vary.
