County Maps US

Summit County, Colorado

A county in Colorado, ranked 19 of 64 by population.

CountyFIPS 08117

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

Download SVGFull Colorado map downloads

Population
31,517
+280 (+0.9%) since 2020
Land area
608.3
square miles. A further 1.8% of the total area is water
Population density
51.8
people per square mile, computed rather than published
County seat
Breckenridge
Seat of county government.
Established
1861
164 years ago
Largest city
Silverthorne town
Population 5,418.

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 Summit 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 Summit County, Colorado 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 730 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 Summit County ranks

Position among the 64 counties of Colorado, and among all 3,144 US counties and county-equivalents. Computed from the figures on this page.

MeasureValueIn ColoradoNationally
Population31,51719th of 641,405th of 3,144
Land area608.3 sq mi55th of 641,595th of 3,144
Population density51.8 per sq mi12th of 641,435th of 3,144
Median household income$109,7735th of 64105th of 3,143

Full data for Summit County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population31,517Vintage 2025 Population Estimates
Population in 202031,237Vintage 2025 Population Estimates
2020 estimates base?31,289Vintage 2025 Population Estimates
Land area608.3 sq mi2025 Gazetteer Files
Water area10.9 sq mi2025 Gazetteer Files
Total area619.3 sq mi2025 Gazetteer Files
Population density?51.8 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$109,773American Community Survey 2020-2024 5-Year Estimates
Median home value$939,900American Community Survey 2020-2024 5-Year Estimates
Median age39.5American Community Survey 2020-2024 5-Year Estimates
Households12,545American Community Survey 2020-2024 5-Year Estimates
Housing units32,251American 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
+188
267 births, 79 deaths
Net migration
-320
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 5 areas bordering Summit 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
Eagle CountyColorado60 mi54,291
Grand CountyColorado40 mi16,496
Park CountyColorado33 mi18,314
Clear Creek CountyColorado20 mi8,994
Lake CountyColorado3.8 mi7,552

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

All 64 counties of Colorado

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

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