County Maps US

Sweetwater County, Wyoming

The largest of Wyoming's 23 counties by land area.

CountyFIPS 56037

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

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Population
41,267
-927 (-2.2%) since 2020
Land area
10,427
square miles. A further 0.6% of the total area is water
Population density
4.0
people per square mile, computed rather than published
County seat
Green River
Seat of county government.
Established
1867
158 years ago
Largest city
Rock Springs city
Population 22,936.

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 Sweetwater 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 Sweetwater County, Wyoming 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 800 by 563 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 Sweetwater County ranks

Position among the 23 counties of Wyoming, and among all 3,144 US counties and county-equivalents. Computed from the figures on this page.

MeasureValueIn WyomingNationally
Population41,2674th of 231,170th of 3,144
Land area10,427 sq mi1st of 2321st of 3,144
Population density4.0 per sq mi13th of 232,832nd of 3,144
Median household income$75,03410th of 23837th of 3,143

Full data for Sweetwater County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population41,267Vintage 2025 Population Estimates
Population in 202042,194Vintage 2025 Population Estimates
2020 estimates base?42,268Vintage 2025 Population Estimates
Land area10,427 sq mi2025 Gazetteer Files
Water area64.2 sq mi2025 Gazetteer Files
Total area10,491 sq mi2025 Gazetteer Files
Population density?4.0 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$75,034American Community Survey 2020-2024 5-Year Estimates
Median home value$251,400American Community Survey 2020-2024 5-Year Estimates
Median age37.9American Community Survey 2020-2024 5-Year Estimates
Households17,502American Community Survey 2020-2024 5-Year Estimates
Housing units19,289American 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
+40
438 births, 398 deaths
Net migration
-126
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 8 areas bordering Sweetwater 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
Carbon CountyWyoming111 mi14,013
Fremont CountyWyoming78 mi39,464
Moffat CountyColorado59 mi13,122
Sublette CountyWyoming52 mi8,929
Daggett CountyUtah50 mi934
Lincoln CountyWyoming48 mi21,180
Uinta CountyWyoming40 mi20,728
Summit CountyUtah2.5 mi43,141

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

All 23 counties of Wyoming

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

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