County facts · Population growth · October 24, 2026
Fastest Growing Counties in Montana, 2020 to 2025
Montana's fastest growing counties by percent and by people added, April 2020 to July 2025 Census estimates, with each official parcel map.
Looking for the fastest growing counties in Montana? From the Census Bureau's April 1, 2020 estimates base to its July 1, 2025 estimate, Montana went from about 1,084,221 to 1,144,694 residents, a change of +60,473 (+5.6%). The fastest growing county by percentage was Broadwater County (+25.4%), while Flathead County added the most people (+11,076, +10.6%).
Every row below links to the county's Platbookmapper page and straight to its official parcel viewer, handy if growth is why you are looking at land there.
Montana growth at a glance
- Counties: 56
- Statewide, April 2020 to July 2025: +60,473 residents (+5.6%); July 2024 to July 2025 alone: +7,137 (+0.6%)
- Grew: 36 of 56 · Lost residents: 20
- Fastest growing by percent: Broadwater County (+25.4%); most people added: Flathead County (+11,076)
- Counties with more deaths than births over the period: 40 of 56
The 10 fastest growing Montana counties by percent
| # | County | Apr 2020 | Jul 2025 | Change | % change | Parcel viewer |
|---|---|---|---|---|---|---|
| 1 | Broadwater County | 6,775 | 8,493 | +1,718 | +25.4% | Montana Cadastral (Montana State Library) |
| 2 | Musselshell County | 4,734 | 5,582 | +848 | +17.9% | Montana Cadastral (Montana State Library) |
| 3 | Madison County | 8,622 | 10,026 | +1,404 | +16.3% | ArcGIS Experience Builder |
| 4 | Mineral County | 4,530 | 5,185 | +655 | +14.5% | ArcGIS Experience Builder |
| 5 | Lincoln County | 19,675 | 22,328 | +2,653 | +13.5% | ArcGIS Web AppBuilder |
| 6 | Sanders County | 12,395 | 14,062 | +1,667 | +13.4% | ArcGIS Instant Apps |
| 7 | Meagher County | 1,926 | 2,137 | +211 | +11.0% | Montana Cadastral (Montana State Library) |
| 8 | Granite County | 3,303 | 3,658 | +355 | +10.7% | Montana Cadastral (Montana State Library) |
| 9 | Flathead County | 104,353 | 115,429 | +11,076 | +10.6% | ArcGIS Web AppBuilder |
| 10 | Jefferson County | 12,081 | 13,329 | +1,248 | +10.3% | ArcGIS Map Viewer |
These 10 added about 21,835 people combined. The median county changed by +2.9%.
The 10 counties that added the most people
| # | County | People added | % change | Jul 2025 | Parcel viewer |
|---|---|---|---|---|---|
| 1 | Flathead County | +11,076 | +10.6% | 115,429 | ArcGIS Web AppBuilder |
| 2 | Gallatin County | +9,783 | +8.2% | 128,740 | ArcGIS Experience Builder |
| 3 | Yellowstone County | +7,966 | +4.8% | 172,692 | county web map |
| 4 | Missoula County | +5,586 | +4.7% | 123,513 | county web map |
| 5 | Ravalli County | +4,407 | +10.0% | 48,582 | ArcGIS Map Viewer |
| 6 | Lewis and Clark County | +4,360 | +6.1% | 75,331 | ArcGIS Web AppBuilder |
| 7 | Lincoln County | +2,653 | +13.5% | 22,328 | ArcGIS Web AppBuilder |
| 8 | Lake County | +2,257 | +7.2% | 33,392 | ArcGIS Instant Apps |
| 9 | Broadwater County | +1,718 | +25.4% | 8,493 | Montana Cadastral (Montana State Library) |
| 10 | Sanders County | +1,667 | +13.4% | 14,062 | ArcGIS Instant Apps |
The top 10 account for about 82% of all the gains in the counties that grew.
Where the new residents came from
The Census Bureau splits each change into natural change (births minus deaths), net domestic migration (moves from other parts of the US) and net international migration. Totals for April 2020 to July 2025 in the five fastest growing counties:
| County | Births minus deaths | Net domestic moves | Net international moves | Total change |
|---|---|---|---|---|
| Broadwater County | +26 | +1,708 | −2 | +1,718 |
| Musselshell County | −89 | +946 | −11 | +848 |
| Madison County | −167 | +1,503 | +70 | +1,404 |
| Mineral County | −137 | +797 | +2 | +655 |
| Lincoln County | −709 | +3,333 | +22 | +2,653 |
In all 5, moves from elsewhere in the US were the biggest source of growth. The three parts do not add up exactly to the total because the Census Bureau also carries a small residual.
The last year alone: July 2024 to July 2025
- Richland County: +2.8% (+306)
- Madison County: +2.6% (+254)
- Broadwater County: +2.5% (+204)
- Musselshell County: +2.4% (+130)
- Judith Basin County: +2.2% (+47)
3 of these 5 are also in the 2020–2025 top 10, so the growth is not a one-year blip.
Counties losing residents
20 of Montana's 56 counties had fewer residents in July 2025 than in April 2020. The steepest declines:
- Wibaux County: −5.5% (−52, now about 885)
- Roosevelt County: −5.2% (−562, now about 10,242)
- Treasure County: −4.2% (−32, now about 728)
- Sheridan County: −3.1% (−111, now about 3,436)
- Fallon County: −3.0% (−90, now about 2,959)
What fast growth means on a parcel map
- New lots show up as plats first. When land is subdivided, the plat is recorded with the county and the parcel layer catches up on its own schedule, so a brand-new lot may not appear on the map for a while. Check the recorder's recent plats if a parcel looks missing.
- Parcel numbers change after splits. A tract that was one parcel last year can be several today. Search by owner name or address as well as by an old parcel number.
- City limits move. Growing cities annex land, which changes who handles zoning and permits even though the county still keeps the deed and the tax map.
- Percent is not the same as people. A small county can post a big percentage on a modest number of new residents, so read the people-added column too.
Related guides
- Largest counties in Montana
- Montana county GIS websites by viewer
- Montana landowner maps for hunting
- Fastest growing counties in the US
- US counties losing population
More: All Montana counties on Platbookmapper
Sources
- U.S. Census Bureau, Population Estimates Program, county totals, Vintage 2025 (April 1, 2020 estimates base and July 1, 2020–2025 estimates, with components of change). Percent change is from the April 1, 2020 estimates base to the July 1, 2025 estimate.
- Platbookmapper county GIS directory (live data file behind our county pages, pulled October 24, 2026) for each official parcel viewer.