Lake County, Montana

A county in Montana, ranked 9 of 56 by population.

CountyFIPS 30047

Within Montana

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

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Population: 33,392; +2,147 (+6.9%) since 2020
Land area: 1,491; square miles. A further 9.9% of the total area is water
Population density: 22.4; people per square mile, computed rather than published
County seat: Polson; Seat of county government.
Established: 1923; 102 years ago
Largest city: Polson city; Population 5,653.

Satellite view

Aerial imagery of Lake 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 Lake 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 616 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 Lake 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.

Measure	Value	In Montana	Nationally
Population	33,392	9th of 56	1,362nd of 3,144
Land area	1,491 sq mi	46th of 56	404th of 3,144
Population density	22.4 per sq mi	7th of 56	2,148th of 3,144
Median household income	$63,360	32nd of 56	1,760th of 3,143

Full data for Lake County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
Measure	Value	Source and vintage
Population	33,392	Vintage 2025 Population Estimates
Population in 2020	31,245	Vintage 2025 Population Estimates
2020 estimates base?	31,135	Vintage 2025 Population Estimates
Land area	1,491 sq mi	2025 Gazetteer Files
Water area	163.5 sq mi	2025 Gazetteer Files
Total area	1,654 sq mi	2025 Gazetteer Files
Population density?	22.4 per sq mi	Computed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income	$63,360	American Community Survey 2020-2024 5-Year Estimates
Median home value	$421,800	American Community Survey 2020-2024 5-Year Estimates
Median age	44.3	American Community Survey 2020-2024 5-Year Estimates
Households	12,576	American Community Survey 2020-2024 5-Year Estimates
Housing units	16,468	American 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: -78; 307 births, 385 deaths
Net migration: +83; 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 3 areas bordering Lake 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 area	State	Shared border	Population
Flathead County	Montana	105 mi	115,429
Sanders County	Montana	77 mi	14,062
Missoula County	Montana	75 mi	123,513

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.