Summit County is a county located in the U.S. state of Colorado. As of the 2010 census, the population was 27,994. The county seat and largest town is Breckenridge. Summit County comprises the Breckenridge, CO Micropolitan Statistical Area.


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.


According to the U.S. Census Bureau, the county has a total area of , of which is land and (1.8%) is water. The terrain of the county is mountainous with elevations ranging from at Green Mountain Reservoir to at Grays Peak. The elevation of the county seat of Breckenridge is , making it one the highest cities in the state of Colorado and the United States. Much of the county has an Alpine (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

*Grand County – north *Clear Creek County – east *Park County – southeast *Lake County – southwest *Eagle County – west

Major Highways

* Interstate 70 * * U.S. Highway 6 * State Highway 9 * State Highway 91


As of the census of 2000, there were 23,548 people, 9,120 households, and 4,769 families residing in the county. The population density was 39 people per square mile (15/km2). There were 24,201 housing units at an average density of 40 per square mile (15/km2). The racial makeup of the county was 91.84% White, 0.68% Black or African American, 0.48% Native American, 0.87% Asian, 0.07% Pacific Islander, 3.96% from other races, and 2.10% from two or more races. 9.79% of the population were Hispanic or Latino of any race. 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. 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. The 2019 average real estate prices in Summit County were $1,262,929 for a single family home, $559,776 for a condo, townhome or duplex and $344,945 for a vacant piece of land (YTD through December 2019). thumb|upright|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. 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. 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.Achenbach, Joel, "U.S. life expectancy varies more than 20 years from county to county," ''Washington Post'', May 8, 2017


Summit County is liberal in most elections.



*Blue River *Breckenridge *Dillon *Frisco *Montezuma *Silverthorne

Census-designated places

*Copper Mountain *Heeney *Keystone

Ghost town

*Dyersville *Kokomo *Parkville *Preston *Saints John *Tiger


National protected areas

*White River National Forest *Eagles Nest Wilderness

Ski areas

* Arapahoe Basin * Breckenridge * Copper Mountain * Keystone

Trails and byways

*American Discovery Trail *Colorado Trail *Continental Divide National Scenic Trail *Great Parks Bicycle Route *Top of the Rockies National Scenic Byway *TransAmerica Trail Bicycle Route *Vail Pass National Recreation Trail *Wheeler Ten Mile National Recreation Trail


The county has two reservoirs, Lake Dillon and Green Mountain Reservoir, that are also popular recreation sites.


* Silver Dollar Island

See also

*Outline of Colorado *Index of Colorado-related articles *National Register of Historic Places listings in Summit County, Colorado *Silverthorne Micropolitan Statistical Area


External links

Colorado County Evolution by Don StanwyckColorado Historical Society
{{authority control Category:Colorado counties Category:1861 establishments in Colorado Territory Category:Populated places established in 1861