About Summit County

Summit County is located among the high peaks of the Colorado Rockies, immediately west of the Continental Divide. Our elevation ranges from a low of 7,947 feet above sea level at Green Mountain Reservoir to a 14,270 feet at Gray’s Peak.

Our dry, high-alpine climate yields long, snowy winters that have attracted world-class ski resorts. We have pleasantly warm summers that are ideal for hiking, biking, fishing, backpacking, kayaking and other forms of recreation.

Summit County is centrally located in Colorado, only an hour’s drive from the Denver metropolitan area via Interstate 70, the state’s main east-west transportation corridor.

Towns, Resorts & Federal Lands

Included within the county are six municipalities (Blue River, Breckenridge, Dillon, Frisco, Montezuma, and Silverthorne), four major ski areas (Arapahoe Basin, Breckenridge, Copper Mountain, and Keystone), portions of the White River National Forest, some Bureau of Land Management lands, and two Congressionally designated wilderness areas (Eagles Nest and Ptarmigan Peak). About 80% of the land in the county is federal public land.

Natural Features

Several striking mountain ranges converge in the county, including portions of the Gore Range, the Tenmile Range, and the Front Range.

Among Summit’s impressive features is the Blue River, generating three times the flow of any other tributary in the Colorado River Basin. The Blue River and its primary tributaries, the Snake River and Tenmile Creek, define the county’s contours, cutting deep valleys into the mountainous terrain.

In the early 1960s, the Denver Water Board dammed the Blue River to create the 2,790-acre Dillon Reservoir, now a popular site for summer recreation. Green Mountain Reservoir, just north of Silverthorne, uses the Blue River to generate power and provide irrigation to nearby ranchlands.

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History of Summit County

Summit County was established in 1861 as one of the Colorado Territory’s original 17 counties. The county border then stretched from the Continental Divide to the Utah line, and from Fremont and Hoosier Passes to the Wyoming line. Six counties were later created from this early Summit County expanse: Grand, Routt, Eagle, Garfield, Moffat and Rio Blanco. Today, Summit County is bounded by the neighboring counties of Clear Creek, Grand, Park, Lake and Eagle.

Gold Rush Days

Summit County first received worldwide attention in 1859 when prospectors discovered gold and silver in the surrounding hills. High country trappers, from 1810-1840, attempted to keep the glittering gold and silver-seamed mountains a secret, but the news filtered out of the remote area to the rest of the United States.

By the summer of 1859, hordes of gold-hungry adventurers scaled the snow-covered Continental Divide to the mineral-rich valley of the Blue River, catapulting this gentle valley from tranquil isolation into the gold rush days. Mine camps lined the Blue River and its tributaries and a parade of colorful characters and scoundrels, like Pug Ryan and Methodist preacher John Lewis Dyer, marched their way on to the pages of history.

Mining Towns & Ski Resorts

Bustling new towns exploded into existence just as quickly as they lapsed into ghost towns, like Parkville, the first county seat. Others, like Breckenridge, Frisco and Dillon, flourished during the days of mining prosperity and clung to life years after the mines played out.

Snow first became became business in Summit County in 1946, when Arapahoe Basin Ski Area opened. With the opening of Breckenridge Ski area in 1961, Keystone in 1970, and Copper Mountain in 1972, “The Summit” became one of the greatest destination ski areas in the nation and was coined “Colorado’s Playground.”

Fast Facts

Summit County Area
396,000 acres
(about 619 square miles)

Annual Precipitation
Approx. 250” snow

Total Number of Housing Units

Average Temperatures
Summer: 68°
Winter: 30°


Sales Tax
State: 2.9%
County: 2%
Breckenridge and Dillon - 2.5%;
Frisco and Silverthorne - 2%

* 2010 Census data

Contact Us

Old County Courthouse
208 E. Lincoln Ave.
Breckenridge, CO 80424
Ph: (970) 453-3470

County Commons
0037 Peak One Dr.
Frisco, CO 80443
Ph: (970) 668-4150

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