Idaho local data guide

Treasure Valley Population Growth Trends (2026)

As of 2026, the Treasure Valley—defined by the Community Planning Association of Southwest Idaho (COMPASS) as Ada, Canyon, Boise, and Elmore counties—has reached a total population of 915,940, with specific high-growth corridors in smaller municipalities like Star and Kuna.

Updated with grounded research as of 2026-09-17.

The short answer

In 2026, the Treasure Valley (comprising Ada, Canyon, Boise, and Elmore counties) reached a total population of 915,940. While regional growth remains steady, the rate varies significantly by geography; smaller cities like Star and Kuna are experiencing rapid annual growth of approximately 14%, compared to roughly 3% in larger hubs like Meridian and Nampa.

Key facts

Total Four-County Population (2026)
915,940 (Ada, Canyon, Boise, and Elmore counties)
Ada & Canyon County Combined Population
876,760
Annual Growth Rate Variation (2026)
14% for Star and Kuna; ~3% for Meridian and Nampa

Regional Growth Overview

The Treasure Valley has seen sustained expansion, with the combined population of Ada and Canyon counties increasing by 150,000 residents—an overall jump of more than 20%—since the 2020 Census. This growth is tracked by the Community Planning Association of Southwest Idaho (COMPASS), which accepted the 2026 estimates on April 27, 2026.

Variation by Municipality

Growth is not uniform across the valley. Planning and relocation decisions should account for the differing expansion rates of municipalities:

  • High-Growth Areas: Smaller municipalities such as Star and Kuna are experiencing rapid annual growth rates of approximately 14%.
  • Established Hubs: Larger metropolitan cities like Meridian and Nampa are growing at a more moderate rate of approximately 3% annually.

Planning Implications

For those involved in housing or local planning, it is critical to note that growth rates fluctuate based on available land, zoning, and infrastructure development. The disparity between the 14% growth in emerging suburbs versus the 3% growth in established city centers often reflects shifts in development patterns as the region manages its rapid expansion.

Common questions

What counties are included in the Treasure Valley definition?

For these statistics, COMPASS defines the Treasure Valley as a four-county region: Ada, Canyon, Boise, and Elmore counties.

Why do growth rates differ so much between cities like Star and Meridian?

Growth rates are influenced by development capacity, zoning, and housing availability. Smaller municipalities often have higher percentage growth rates due to rapid new construction on previously undeveloped land, whereas larger, more established cities see slower percentage growth relative to their already significant total population.

Related Idaho questions

  • What is the population forecast for the Treasure Valley in 2030?
  • How does COMPASS calculate population estimates?

Sources and verification