Idaho’s growth is a migration story, not a birth-rate story. The Census Bureau’s Vintage 2025 estimates put the state’s increase in the year to 1 July 2025 at 28,861 people. Net domestic migration — arrivals from other states minus departures to them — supplied 19,915 of that. Births exceeded deaths by 6,900, and net international migration added 2,148.
The three components, year by year
| Year to 1 July | Births minus deaths | Net domestic migration | Net international migration |
|---|---|---|---|
| 2021 | +4,731 | +52,350 | +699 |
| 2022 | +3,436 | +28,019 | +5,908 |
| 2023 | +5,528 | +14,713 | +7,179 |
| 2024 | +6,086 | +15,975 | +8,154 |
| 2025 | +6,900 | +19,915 | +2,148 |
Source: the Bureau’s Vintage 2025 components-of-change file. Domestic migration peaked in the year to July 2021 at 52,350, fell by three quarters over the two years after it, and has climbed again since. Measured per thousand residents, Idaho’s net domestic migration in the year to July 2025 was 9.9 — second among the states behind South Carolina’s 12.0. Where that leaves Idaho in the overall ranking is set out in whether Idaho is the fastest-growing state.
Where the movers come from
The American Community Survey publishes a full state-to-state flow table each year. These are the largest flows into Idaho in the 2024 table, with the survey’s margins of error:
| Previous residence | People who moved to Idaho | Margin of error |
|---|---|---|
| Washington | 17,837 | ±3,554 |
| California | 15,385 | ±2,919 |
| Abroad | 8,112 | ±1,745 |
| Utah | 5,417 | ±1,302 |
| Arizona | 4,511 | ±1,645 |
| Oregon | 4,206 | ±1,226 |
| Nevada | 3,270 | ±1,674 |
Gross arrivals are only half the picture. The same table counts people leaving, and the net figures reorder the list: Idaho gained 9,910 people on Washington and 8,876 on California, but lost 2,976 to Utah, 1,205 to Texas and 619 to Arizona. The Pacific Northwest and California are what make Idaho’s net inflow; the interior West largely trades even with it, and the Utah exchange runs the other way.
What official numbers say about the pull
No federal agency publishes a reason for moving alongside these flows, so the honest answer is that the sources measure the movement, not the motive. What they do measure is the gap the movers are crossing. The Bureau of Economic Analysis puts the regional price parity for the whole of Idaho at 95.5 in 2024, against a national level of 100 — and for services other than housing and utilities the state sits below the national level too. Idaho’s price level is lower than the states sending it the most people, and that gap has been there through the whole run.
The counterweight is that housing inside Idaho has not stayed cheap: the state’s housing price parity rose from 73.8 in 2016 to 90.0 in 2024, and in the Boise metro it passed the national level entirely. That is the subject of what Boise costs against the national average.
The jobs side of the same question — what the arrivals are moving toward — is in what is driving Idaho’s boom, and the share of all this landing in one metro is on the Boise population page.