County Maps US

Gallatin County, Montana

A county in Montana, ranked 2 of 56 by population.

CountyFIPS 30031

Within Montana
Gallatin County, highlighted, with the areas around it. Boundaries generalised from the 2025 Census cartographic boundary file; neighbour fills carry no data. The dot marks Bozeman, the county seat, located via the 2025 Census Gazetteer.

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Population
128,740
+9,147 (+7.6%) since 2020
Land area
2,605
square miles. A further 1.1% of the total area is water
Population density
49.4
people per square mile, computed rather than published
County seat
Bozeman
Seat of county government.
Established
1864
161 years ago
Largest city
Bozeman city
Population 58,814.

Sources: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026; US Census Bureau, Gazetteer Files, 2025 Gazetteer Files, released 10 September 2025; Wikidata (CC0), Wikidata. Retrieved 30 August 2026.

Satellite view

Aerial imagery of Gallatin County with its boundary drawn on top. A map shows you the shape; this shows you what is inside it, and which side of the line a place falls on.

Aerial view of Gallatin County, Montana from the USGS National Map, with its boundary outlined
Imagery: USGS National Map, USGS Imagery Only, public domain, requested from USGS by your browser when you reach this point on the page, at 385 by 800 pixels. The boundary is the 2025 Census cartographic boundary file, reprojected to Web Mercator to match the imagery. You can also open the USGS National Map viewer.

Where Gallatin County ranks

Position among the 56 counties of Montana, and among all 3,144 US counties and county-equivalents. Computed from the figures on this page.

MeasureValueIn MontanaNationally
Population128,7402nd of 56514th of 3,144
Land area2,605 sq mi24th of 56204th of 3,144
Population density49.4 per sq mi3rd of 561,484th of 3,144
Median household income$93,5282nd of 56241st of 3,143

Full data for Gallatin County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population128,740Vintage 2025 Population Estimates
Population in 2020119,593Vintage 2025 Population Estimates
2020 estimates base?118,957Vintage 2025 Population Estimates
Land area2,605 sq mi2025 Gazetteer Files
Water area28.4 sq mi2025 Gazetteer Files
Total area2,634 sq mi2025 Gazetteer Files
Population density?49.4 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$93,528American Community Survey 2020-2024 5-Year Estimates
Median home value$667,600American Community Survey 2020-2024 5-Year Estimates
Median age34.2American Community Survey 2020-2024 5-Year Estimates
Households51,215American Community Survey 2020-2024 5-Year Estimates
Housing units57,568American Community Survey 2020-2024 5-Year Estimates

Sources: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026; US Census Bureau, Gazetteer Files, 2025 Gazetteer Files, released 10 September 2025; US Census Bureau, American Community Survey, American Community Survey 2020-2024 5-Year Estimates, released 29 January 2026. Population density is computed here, not published: it divides the Vintage 2025 population estimate by the 2025 Gazetteer land area, which are two different Census products. Retrieved 30 August 2026.

How the population changed

The Census Bureau publishes the components behind an estimate, not just the total. For the year to July 2025:

Births minus deaths
+437
1,137 births, 700 deaths
Net migration
+799
More people moved in than moved out.

Source: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026. Retrieved 30 August 2026.

The 8 areas bordering Gallatin County

Ordered by the length of the border actually shared, which the Census Bureau publishes in its county adjacency file and which no other county reference presents.

Bordering areaStateShared borderPopulation
Madison CountyMontana96 mi10,026
Park CountyMontana95 mi18,214
Broadwater CountyMontana53 mi8,493
Fremont CountyIdaho33 mi14,208
Park CountyWyoming24 mi31,171
Meagher CountyMontana13 mi2,137
Teton CountyWyoming13 mi23,333
Jefferson CountyMontana9.8 mi13,329

Source: US Census Bureau, County Adjacency File, 2025 County Adjacency File, released 15 September 2025. Retrieved 30 August 2026.

All 56 counties of Montana

Open the interactive Montana county map, or jump straight to any of them.

Data on this page last rebuilt 30 August 2026. How these figures are produced.