Colorado population growth slows to its lowest in decades

Colorado’s population officially topped six million people in 2025, according to new U.S. Census estimates. But the milestone came with a major slowdown in growth.

The state grew by just 0.4 percent in the year ending July first, its slowest growth rate since 1989. That puts Colorado 29th nationally, behind the overall U.S. growth rate of 0.5 percent and far behind fast-growing states like Texas, South Carolina, Idaho, and North Carolina.

State Demographer Kate Watkins says Colorado is no longer attracting new residents the way it once did. For the first time in decades, the state recorded a net loss of population to other states, with about 12-thousand more people moving out than moving in.

That’s a dramatic change from the 2010s, when Colorado regularly gained tens of thousands of residents each year from domestic migration. The flow of new residents slowed after the pandemic, and in 2025 it turned negative.

Watkins says high housing costs, crowding, and job opportunities elsewhere are among the likely reasons people are leaving. Some departures also include recent immigrants who arrived in large numbers in 2023 and 2024, then moved on to other states.

International immigration to Colorado has also dropped sharply, falling from more than 50-thousand arrivals per year at its peak to about 15-thousand in the most recent estimates.

Despite slower migration, Colorado’s population still grew thanks to natural increase. Births exceeded deaths by more than 20-thousand people, accounting for most of the state’s overall growth.

The Denver metro area continues to see the largest population gains, followed by Greeley and Colorado Springs.