Summit County, Colorado

Last updated
Summit County, Colorado
County
Summit County court house in Colorado.jpg
The Summit County Courthouse in Breckenridge
Seal of Summit County, Colorado.png
Seal
Map of Colorado highlighting Summit County.svg
Location within the U.S. state of Colorado
Colorado in United States.svg
Colorado's location within the U.S.
Coordinates: 39°37′16″N106°08′15″W / 39.621023°N 106.137555°W / 39.621023; -106.137555
CountryFlag of the United States.svg United States
StateFlag of Colorado.svg Colorado
FoundedNovember 1, 1861
Named after Continental Divide
Seat Breckenridge
Largest town Silverthorne
Area
 • Total
619.259 sq mi (1,603.87 km2)
 • Land608.328 sq mi (1,575.56 km2)
 • Water10.931 sq mi (28.31 km2)  1.77%
Population
 (2020)
 • Total
31,055
 • Estimate 
(2024)
30,882 Decrease2.svg
 • Density51.050/sq mi (19.710/km2)
Time zone UTC−7 (Mountain)
 • Summer (DST) UTC−6 (MDT)
Area code 970 and 748
Congressional district 2nd
Website summitcountyco.gov

Summit County is a county located in the U.S. state of Colorado. As of the 2020 census, the population was 31,055, [1] and was estimated to be 30,882 in 2024. [2] The county seat of Breckenridge. [3] Summit County comprises the Breckenridge, CO Micropolitan Statistical Area. [4] [5]

Contents

History

Summit County was organized as one of the seventeen original Colorado counties by the First Territorial Legislature on November 1, 1861. It was named for the many mountain summits in the county. Until February 2, 1874, its boundaries included the area now comprising Summit County, Grand County, Routt County, Moffat County, Garfield County, Eagle County, and Rio Blanco County.

In 1874, the northern half of the original Summit County was split off to form Grand County; with the creation of Garfield and Eagle counties in 1883, Summit County arrived at its present boundaries. In addition, Summit County has seen two major boom eras.

Geography

According to the United States Census Bureau, the county has a total area of 619.259 square miles (1,603.87 km2), of which 608.328 square miles (1,575.56 km2) is land and 10.931 square miles (28.31 km2) (1.77%) is water. [6] It is the 55th largest county in Colorado by total area. [7]

The terrain of the county is mountainous with elevations ranging from 7,957 feet (2,425 m) at Green Mountain Reservoir to 14,270 feet (4,350 m) at Grays Peak. The elevation of the county seat of Breckenridge is 9,602 feet (2,927 m), making it one of the highest cities in the state of Colorado and the United States. [8] Much of the county has an alpine climate (ET in the Köppen Classification) characterized by tundra vegetation. Breckenridge and other similar elevations in the county have a subarctic climate (Dfc) characterized by cool summers and abundant snowfall in winter.

Adjacent counties

Major highways

Demographics

Historical population
CensusPop.Note%±
1870 258—
1880 5,4592,015.9%
1890 1,906−65.1%
1900 2,74444.0%
1910 2,003−27.0%
1920 1,724−13.9%
1930 987−42.7%
1940 1,75477.7%
1950 1,135−35.3%
1960 2,07382.6%
1970 2,66528.6%
1980 8,848232.0%
1990 12,28138.8%
2000 23,54891.7%
2010 27,99418.9%
2020 31,05510.9%
2024 (est.)30,882 [9] −0.6%
U.S. Decennial Census [10]
1790–1960 [11] 1900–1990 [12]
1990–2000 [13] 2010–2020 [2]

2000 census

As of the 2000 census, there were 23,548 people, 9,120 households, and 4,769 families residing in the county. The population density was 39.0 inhabitants per square mile (15.1/km2). There were 24,201 housing units at an average density of 40.0 per square mile (15.4/km2). The racial makeup of the county was 91.84% White, 0.68% African American, 0.48% Native American, 0.87% Asian, 0.07% Pacific Islander, 3.96% from some other races and 2.10% from two or more races. Hispanic or Latino people of any race were 9.79% of the population.

There were 9,120 households, out of which 24.00% had children under the age of 18 living with them, 44.00% were married couples living together, 4.40% had a female householder with no husband present, and 47.70% were non-families. 21.60% of all households were made up of individuals, and 1.60% had someone living alone who was 65 years of age or older. The average household size was 2.48 and the average family size was 2.86.

In the county, the population was spread out, with 17.40% under the age of 18, 15.70% from 18 to 24, 44.30% from 25 to 44, 19.40% from 45 to 64, and 3.30% who were 65 years of age or older. The median age was 31 years. As of 2014, the life expectancy in Summit County was 86.83 years, the longest average life expectancy of any county in the United States. [14] For every 100 females there were 139.00 males. For every 100 females age 18 and over, there were 144.90 males.

The median income for a household in the county was $56,587, and the median income for a family was $66,914 (these figures had risen to $65,281 and $80,441 respectively as of a 2007 estimate). Males had a median income of $33,741 versus $27,017 for females. The per capita income for the county was $28,676. About 3.10% of families and 9.00% of the population were below the poverty line, including 4.30% of those under age 18 and 3.40% of those age 65 or over.

Snowmelt runoff fills Lake Dillon in Summit County Reservoir in the Rocky Mountains.jpg
Snowmelt runoff fills Lake Dillon in Summit County

Life expectancy

According to a report in the Journal of the American Medical Association, residents of Summit County had a 2014 life expectancy from birth of 86.83 years in 2014, the longest in the United States. [15] Both men and women live longer in Summit County than in any other county in the United States: 85.5 years for men and 88.0 years for women is the life expectancy at birth. [16] Two contiguous counties, Pitkin and Eagle Counties, rank numbers two and three in the nation in life expectancy. Factors contributing to the high life expectancy in Summit County are "high education, high income, high access to medical care, the people are physically active, obesity is lower than anywhere else — so you’re doing it right,” said Dr. Ali Mokdad, one of the study's co-authors. [17]

Education

K–12 schools

Elementary schools

  • Breckenridge Elementary School
  • Dillon Valley Elementary School (Dillon)
  • Frisco Elementary School
  • Silverthorne Elementary School
  • Summit Cove Elementary School (Dillon)
  • Upper Blue Elementary School (Breckenridge)

Middle school

  • Summit Middle School (Frisco)

High schools

  • Snowy Peaks Junior/Senior High School (Frisco)
  • Summit High School (between Frisco and Breckenridge)

Higher education

Colorado Mountain College operates campuses in Breckenridge and Dillon.

Politics

Summit County is liberal in most elections. Since 1988 the county has trended strongly toward the Democratic Party, like many other counties in Colorado dominated by ski towns. In 2020, Joe Biden's performance was the best by a Democrat since 1916, and Kamala Harris' performance was only slightly worse in 2024.

United States presidential election results for Summit County, Colorado [18]
Year Republican Democratic Third party(ies)
No. %No. %No. %
1880 1,28948.81%1,32850.28%240.91%
1884 60951.92%55647.40%80.68%
1888 70155.63%55744.21%20.16%
1892 27925.60%00.00%81174.40%
1896 282.20%1,24397.64%20.16%
1900 39428.59%96770.17%171.23%
1904 56148.15%56948.84%353.00%
1908 36631.99%74364.95%353.06%
1912 17918.55%60062.18%18619.27%
1916 26826.27%71770.29%353.43%
1920 41850.36%38846.75%242.89%
1924 35447.52%24132.35%15020.13%
1928 36253.16%30644.93%131.91%
1932 22434.78%39761.65%233.57%
1936 26834.85%49664.50%50.65%
1940 47946.78%54052.73%50.49%
1944 32657.60%23741.87%30.53%
1948 29243.26%37856.00%50.74%
1952 44261.90%27137.96%10.14%
1956 42964.61%23535.39%00.00%
1960 42451.27%40048.37%30.36%
1964 34441.55%48358.33%10.12%
1968 53657.39%30132.23%9710.39%
1972 1,08259.03%70738.57%442.40%
1976 1,82658.15%1,08734.62%2277.23%
1980 2,02746.54%1,28529.51%1,04323.95%
1984 3,25366.14%1,58832.29%771.57%
1988 2,89351.44%2,59546.14%1362.42%
1992 2,25626.95%3,34439.95%2,77033.09%
1996 3,26138.73%3,97047.16%1,18814.11%
2000 4,49740.63%5,30447.92%1,26711.45%
2004 5,37039.10%8,14459.29%2211.61%
2008 4,88332.77%9,80265.79%2141.44%
2012 5,57136.38%9,34761.04%3942.57%
2016 5,10031.53%9,55759.09%1,5179.38%
2020 5,32228.80%12,63168.35%5262.85%
2024 5,24429.89%11,76267.04%5393.07%

Communities

Towns

Census-designated places

Ghost towns

Recreation

National protected areas

Ski areas

Trails and byways

Lakes

The county has three reservoirs, Lake Dillon, Green Mountain Reservoir, and Clinton Gulch Dam Reservoir that are also popular recreation sites.

Islands

Concert venues

See also

References

Gold specimen from the Breckenridge Mining District Gold-221311.jpg
Gold specimen from the Breckenridge Mining District
  1. ↑ "Explore Census Data". United States Census Bureau . Retrieved November 29, 2025.
  2. 1 2 "U.S. Census Bureau QuickFacts: Summit County, Colorado". www.census.gov. Retrieved November 29, 2025.
  3. ↑ "Find a County". National Association of Counties . Retrieved November 29, 2025.
  4. ↑ "OMB Bulletin No. 10-02: Update of Statistical Area Definitions and Guidance on Their Uses" (PDF). Office of Management and Budget . December 1, 2009. Archived (PDF) from the original on January 21, 2017. Retrieved April 19, 2012– via National Archives.
  5. ↑ See the Colorado census statistical areas.
  6. ↑ "2025 County Gazetteer Files – Colorado". United States Census Bureau . Retrieved November 29, 2025.
  7. ↑ "U.S. Census Bureau QuickFacts: Summit County, Colorado". www.census.gov. Retrieved November 29, 2025.
  8. ↑ "Elevation distribution for all U.S. cities," http://www.city-data.com/top13.html, accessed August 2, 2017
  9. ↑ "County Population Totals and Components of Change: 2020-2024" . Retrieved June 3, 2025.
  10. ↑ "U.S. Decennial Census". United States Census Bureau. Retrieved June 11, 2014.
  11. ↑ "Historical Census Browser". University of Virginia Library. 2007. Archived from the original on December 12, 2009. Retrieved June 11, 2014.
  12. ↑ Forstall, Richard L. (March 27, 1995). "Population of Counties by Decennial Census: 1900 to 1990". United States Census Bureau. Archived from the original on February 19, 1999. Retrieved June 11, 2014.
  13. ↑ "Census 2000 PHC-T-4. Ranking Tables for Counties: 1990 and 2000" (PDF). United States Census Bureau. Archived (PDF) from the original on March 27, 2010. Retrieved June 11, 2014.
  14. ↑ "US Health Map". Institute for Health Metrics and Evaluation . University of Washington. Retrieved May 8, 2017.
  15. ↑ Dwyer-Lindgren, Laura (May 8, 2017). "Inequalities in Life Expectancy Among US Counties, 1980 to 2014". JAMA Internal Medicine. 177 (7): 1003–1011. doi:10.1001/jamainternmed.2017.0918. PMC   5543324 . PMID   28492829.
  16. ↑ "County Profile: Summit County Colorado," http://www.healthdata.org/sites/default/files/files/county_profiles/US/2015/County_Report_Summit_County_Colorado.pdf, accessed August 2, 2017
  17. ↑ Achenbach, Joel, "U.S. life expectancy varies more than 20 years from county to county," Washington Post, May 8, 2017
  18. ↑ Leip, David. "Dave Leip's Atlas of U.S. Presidential Elections". uselectionatlas.org. Retrieved May 26, 2017.
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