Treasure Valley population growth in 2026: where 28,920 additional residents were counted

COMPASS estimates 589,500 residents in Ada County and 287,260 in Canyon County for 2026. The combined total of 876,760 is 28,920 above the comparable 2025 estimate of 847,840, a one-year increase of 3.4%.

That regional total matters because housing demand, transportation, utilities, schools, and employment space operate across city boundaries. It should not be read as one uniform real estate market. The location, price band, product type, infrastructure, and timing still determine whether demand reaches a specific property.

Ada County added an estimated 17,480 residents, moving from 572,020 to 589,500. That is a 3.1% increase. Canyon County added 11,440, moving from 275,820 to 287,260, a 4.1% increase.

The distinction between absolute and percentage growth is important. Ada still absorbed the larger number of people, but Canyon expanded faster from a smaller base. That can increase pressure on roads, utility extensions, schools, and housing delivery in places where the development system is already changing quickly.

Caldwell recorded the largest absolute increase among the nine Atlas cities at 5,160 residents. Kuna added 4,810, Meridian 4,730, Nampa 3,590, and Star 3,290. Boise remained the largest city and added 2,900 residents.

Star and Kuna posted the fastest percentage changes at 14.7% and 14.3%. Those rates are mathematically affected by smaller starting populations, so they should be read alongside the absolute additions and the capacity of each city's infrastructure and entitlement pipeline.

The nine Atlas cities added a combined 27,430 residents. That equals 94.8% of the 28,920-person increase across Ada and Canyon counties. The remaining 1,490 were distributed across unincorporated Ada and Canyon counties and the smaller Canyon County cities not included in the nine-city comparison.

This reconciliation prevents a common analytical error: adding selected city figures and presenting the result as the entire region. City-limit estimates also differ from postal addresses, school districts, fire districts, and real estate search areas, which may extend beyond municipal boundaries.

Sustained population additions can support household formation and increase the need for housing and services. Fast growth can also expose constraints: sewer and water capacity, transportation improvements, school enrollment, emergency services, entitlement throughput, and the pace at which finished lots and homes reach the market.

For an acquisition or development decision, population is a market-screening input. It should be paired with current inventory, resale and rental evidence, planned and permitted supply, achievable density, utility availability, development conditions, construction costs, financing, and a realistic delivery schedule.

Atlas transcribed the 2025 and 2026 values from the COMPASS Historic Population Estimates by City Limits and calculated one-year changes and percentages. Star's Ada and Canyon county portions were combined. Eagle's Ada and Boise county portions were combined. Percentages are rounded to one decimal place.

COMPASS estimates municipal and county populations using its own method and release schedule. They are not interchangeable with Census estimates from another vintage. Annexations and boundary changes can also affect city-limit comparisons, so a large change should not automatically be attributed only to household movement or new construction.