Colorado population hits 6,011,146 despite migration dip
State demographers report the population rose by 23,725 residents last year, driven by births and international arrivals even as out-migration turned negative for the first time in two decades.
By Jillian Foster ·
The population of Colorado reached 6,011,146 as of July 1, 2025, according to new data presented by state demographers. This figure represents an increase of 23,725 people, or 0.4 percent, from the previous year. The growth marks a continuation of a long-term trend, with state models projecting the population to reach approximately 7.5 million by 2060.
State demographer Neal Marquez, who took office in July, addressed concerns about a supposed downward spiral in the state's demographics. He noted that while national news often cites population decline, Colorado continues to grow at a rate faster than the national average. Marquez stated that this pattern is expected to persist over the next two to three decades.
The population increase was fueled primarily by natural growth and international migration. The state recorded its highest number of births since 2017, adding 20,000 people to the total when accounting for births minus deaths. International migration contributed another net 15,000 residents over the past year.
Domestic migration, however, shifted in the opposite direction. Colorado experienced a net loss of approximately 3,451 people who moved to other states during the 12 months ending in July 2025. This was the first negative domestic migration figure for the state since the early 2000s. Officials attributed this decline partly to the movement of humanitarian migrants who had been transported to Colorado from other states in 2023 and 2024 but did not remain in the state.
Local trends varied significantly across the state's 64 counties. While the state overall grew, 23 counties lost population. Jefferson and Boulder counties suffered the largest losses, shedding about 3,302 and 2,442 residents, respectively. In contrast, Weld County gained 46,639 people, driven by both higher birth rates and an influx of new residents.
State economist Greg Totten linked the drop in domestic migration to changes in the job market. Colorado lost 4,898 jobs last year, the first such decline outside of a recessionary period in recent history. The state's payroll job growth since 2001 has reached 32 percent, compared to 20 percent nationwide, but that 12-point lead has narrowed to 0.9 points. Totten cited declines in construction, information, and finance sectors as key factors, noting that construction work has increasingly moved to data centers elsewhere.
The healthcare industry remained a strong performer, adding more than 13,300 jobs. However, other sectors combined for a net loss of 18,300 jobs. Hanna Scovill, a senior economist at Pacey Economics, observed that Colorado is becoming more middle of the pack in terms of business attraction. She emphasized that the state's reliance on a highly educated workforce makes it sensitive to changes in net migration.
The data presented at the State Demography Summit also included long-term projections. Fertility rates are stabilizing, and the under-18 population, which declined after 2020, is expected to level off. Life expectancy is projected to rise from 79.9 in 2024 to 83.4 by 2060. Demographers noted that these figures help lawmakers understand future resource needs without setting specific policy.
The analysis did not account for the impact of Amendment 87, which will raise the income tax rate for the state's highest earners and businesses. Both Gov. Jared Polis and governor-elect Phil Weiser opposed the measure, arguing it could discourage corporate investment. The state's demographic profile is also becoming more diverse, with the composition of the population shifting over the last decade and expected to change further in the next ten years.
