Summit County is located among the high peaks of the Colorado Rockies, just on the west side of the Continental Divide. Perhaps the county’s most majestic characteristic is its towering altitude, from a low of 7,947 feet above sea level at Green Mountain Reservoir to a sky-scraping 14,270 feet at Gray’s Peak. This high and dry climate blesses the region with powdery white snow in the winter and pleasantly warm, sunny days in the summer. Several mountain ranges converge in the county, including portions of the Gore Range, the Tenmile Range, and the Front Range.
The county is centrally located in Colorado, being only an hour’s drive from the Denver metropolitan area. Interstate 70 (I-70), the state’s main east-west transportation corridor, bisects the county and enhances the proximity of the county to Denver / Front Range communities. This proximity to a large metropolitan area has contributed greatly to the county’s popularity as a mountain recreational area.
Included within the county are six municipalities (Blue River, Breckenridge, Dillon, Frisco, Montezuma, and Silverthorne), four major ski resorts (Arapahoe Basin, Breckenridge, Copper Mountain, and Keystone), significant national forest and Bureau of Land Management lands, and two congressionally designated wilderness areas (Eagles Nest and Ptarmigan Peak). Roughly 80% of the land in the county is public land managed by the U.S. Forest Service and Bureau of Land Management.
Among Summit’s impressive features is the beautiful Blue River, generating three times the flow of any other river contributing to the Colorado River Basin. In the early 1960s, the Denver Water Board took advantage of this river’s peak water flow and dammed the Blue River to create the 2,790-acre Dillon Reservoir. Green Mountain Reservoir, just north of Silverthorne, also utilizes the Blue River to generate power and provide irrigation to nearby ranchlands. The Blue River and its primary tributaries, the Snake River and the Tenmile Creek, define the county’s contours, cutting deep valleys into the area’s mountainous terrain.