County Maps US

Blaine County, Montana

A county in Montana, ranked 31 of 56 by population.

CountyFIPS 30005

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

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Population
6,860
-149 (-2.1%) since 2020
Land area
4,228
square miles. A further 0.3% of the total area is water
Population density
1.6
people per square mile, computed rather than published
County seat
Chinook
Seat of county government.
Established
1912
113 years ago
Largest city
Chinook city
Population 1,155.

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 Blaine 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 Blaine 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 573 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 Blaine 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
Population6,86031st of 562,666th of 3,144
Land area4,228 sq mi9th of 56110th of 3,144
Population density1.6 per sq mi39th of 563,020th of 3,144
Median household income$64,81329th of 561,650th of 3,143

Full data for Blaine County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population6,860Vintage 2025 Population Estimates
Population in 20207,009Vintage 2025 Population Estimates
2020 estimates base?7,046Vintage 2025 Population Estimates
Land area4,228 sq mi2025 Gazetteer Files
Water area11.2 sq mi2025 Gazetteer Files
Total area4,239 sq mi2025 Gazetteer Files
Population density?1.6 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$64,813American Community Survey 2020-2024 5-Year Estimates
Median home value$155,500American Community Survey 2020-2024 5-Year Estimates
Median age35.6American Community Survey 2020-2024 5-Year Estimates
Households2,280American Community Survey 2020-2024 5-Year Estimates
Housing units2,823American 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
+1
81 births, 80 deaths
Net migration
-17
More people moved out than moved in.

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

The 4 areas bordering Blaine 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
Phillips CountyMontana126 mi4,203
Hill CountyMontana67 mi16,167
Fergus CountyMontana42 mi11,825
Chouteau CountyMontana28 mi5,865

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.