Summit County is a mountainous county in central Colorado, approximately sixty-five miles west of Denver. Originally one of the largest of Colorado’s first seventeen counties, Summit County’s current border connects a ring of peaks around an area of 619 square miles. It is bordered to the north by Grand County, to the east by Clear Creek County, to the south by Park and Lake Counties, and to the west by Eagle County. Summit County has a full-time population of 27,994; major towns include the county seat of Breckenridge (pop. 4,564), Silverthorne (pop. 3,887), Frisco (pop. 2,683), and Keystone (pop. 1,079). State Route 9 follows the Blue River on a north-south path through the county, intersecting with Interstate 70 in Silverthorne.
The county is named for the many tall peaks within its borders, which encompass large sections of the Front, Tenmile, and Gore Ranges of the Rocky Mountains. At 14,271 feet, Quandary Peak is the highest point in the county and the thirteenth-highest mountain in Colorado. The Blue River begins at the confluence of Monte Cristo and Bemrose Creeks in southern Summit County, near the Quandary Peak trailhead. The river is dammed twice before it leaves Summit County: first at Dillon Reservoir, created in 1963 to divert more water to the Platte River basin, and then farther downstream at Green Mountain Reservoir, which was finished in 1942 as the first part of the Colorado-Big Thompson Project. The White River National Forest covers nearly the entire county.
For several thousand years, the Summit County area served as hunting grounds for nomadic indigenous people, most recently the Nuche or Ute people. Major gold finds in the mid-nineteenth century drove the county’s development, and today it is home to many popular ski resorts, including Arapahoe Basin, Breckenridge, Keystone, and Copper Mountain.
From about the mid-sixteenth century until the late nineteenth century, the Summit County area was inhabited by two distinct bands of Utes: the Parianuche, or “Elk People,” and the Yampa, or “Root Eaters.” Both groups ranged across the northern half of Colorado’s Rocky Mountains, following centuries-old seasonal migration patterns. They fished and hunted elk, deer, bison, and other mountain game. They also gathered a wide assortment of wild berries and roots, including the versatile yucca root. In the summer, they followed game up to the headwaters and the high country, and in the winter they returned to the shelter of lower elevations in places such as South Park.
The Arapahos, pushed out of their homeland in the Upper Midwest by conflict with other native groups, arrived on Colorado’s plains by the early 1820s. The Arapaho also followed a seasonal migration route, tracking game up to the high country in the Summit County area during the summer and returning to the edge of the foothills for the winter. The Utes, meanwhile, had been ranging out of their mountain homeland for summer buffalo hunts since the late seventeenth century; the overlapping territory was often a source of tension and conflict between the Ute and Arapaho peoples.
Trappers, Traders, and Miners
Soon, the Utes and Arapahos had more to contend with than just each other. Fur trappers and traders frequented the Summit County area from the early 1800s to the 1840s. The current area of Dillon Reservoir, at the confluence of the Snake and Blue Rivers and Tenmile Creek, was then known as LaBonte’s Hole, a rendezvous point for trappers, traders, and Native Americans.
The first gold seekers arrived in the Summit County area in 1859. In August, a prospecting party led by Ruben J. Spaulding, a miner who participated in the 1849 California Gold Rush, found gold in Georgia Gulch a few miles northeast of present-day Breckenridge.
In 1860 George Spencer of the prospecting firm Spencer & Company founded the town of Breckenridge. Historians still debate the origins of the town’s name. The most recent argument, put forth by local historians Bill Fountain and Robin Theobald, is that the settlement was likely named for an early resident, Thomas Breckenridge, and the spelling was later changed to “Breckinridge” when Spencer tried to flatter US Vice President John C. Breckinridge into awarding the town a post office. The current spelling reflects the former resident Breckenridge, and may have been changed in an attempt to disassociate the town from the vice president after he pledged support to the Confederacy. In any case, the diggings around the new town proved rich: by the end of the decade, some $5.5 million worth of gold had been extracted from the Breckenridge area.
In 1861, Summit County became one of the original seventeen counties of the Colorado Territory. When it was first established, Summit was an enormous county that covered nearly the entire northwestern quadrant of the new territory. The creation of Grand County in 1874 reduced Summit's size by about half. Colorado joined the Union in 1876, and in 1883 Summit County was pared down to its current size by the creation of Garfield and Eagle Counties.
Removal of Native Americans
The gold discoveries at Cherry Creek, Clear Creek, and Georgia Gulch in 1858-59 proved to be the beginning of the end of the Utes’ 500-year dominance in the Rockies. Seeking to protect the new mining districts along the Front and Tenmile Ranges, the federal government brokered the Treaty of 1868, which reserved for the Utes most of the land in Colorado west of the Continental Divide. Meanwhile, after a protracted conflict with the US government following the Sand Creek Massacre in 1864, the Arapahos and their Cheyenne allies were removed to present-day Oklahoma via the Medicine Lodge Treaty of 1867.
In 1879 Utes at the White River Indian Agency in northwestern Colorado revolted, killing Indian Agent Nathan Meeker and a handful of his employees. Terrified whites demanded swift action from the federal government, and in 1880 a new treaty was brokered that took all of the Utes’ land in Colorado. Over the next several years, most of the Parianuche and Yampa Utes were forced onto a new reservation in eastern Utah. The Utes’ stewardship of the Blue River valley had come to an end. While Native American hunting and horses affected the local ecology, the Utes’ environmental legacy paled in comparison to the effects of later activities such as mining, large-scale water diversion, and the construction of roads, railroads, and ski resorts.
Between 1859 and 1879, several different mining processes helped Summit County produce nearly $7 million in gold. As early as 1863, the surface gold in Summit County mines began to be depleted. To reach deeper deposits, miners turned to a process called hydraulic mining, which uses high-pressure hoses to blast away rock and free gold tumbling down through sluices. The gold would then sink to the bottom of the sluices, where it was recovered the same way it was in the panning process. Hard-rock mining, or the manual extraction of gold and silver in mine tunnels, was also employed to get at deeper deposits.
In addition, a number of silver lodes were discovered in the area during the 1870s, and Summit County soon found itself in the midst of a second mining boom. The center of mining production shifted from the Breckenridge area to the Tenmile Mining District near Frisco, which produced an estimated $2 million in silver in 1881.
When gold deposits seemed to be depleted again in the late nineteenth century, miners applied modern industrial technology to the ancient concept of gold panning, creating monstrous machines called dredges. A dredge was a floating platform equipped with a motorized bucket that dug up loads of rock from a riverbed and dumped them into rotating steel cylinders. The cylinders allowed small materials, including gold, to filter down into a sluice while jettisoning larger pieces of waste rock off the back of the dredge via a conveyer belt.
Benjamin S. Revett, a mining mogul known as the “Father of Gold Dredging in the United States,” began operating Colorado’s first dredge in Summit County in 1898. Revett operated three other experimental dredges in the late nineteenth century and early twentieth, but dredging in Summit County did not take off until after 1906, when Revett’s Reliance dredge in French Gulch reportedly began producing $1,000 of gold per day. In all, Revett operated seven dredge boats in Summit County between 1898 and 1942.
Gold panning, hydraulic mining, and hard-rock mining provided well-paid jobs for many, made the fortunes of few, and helped to develop Summit County economically. But these practices also had devastating effects on the local environment. To increase their payload, miners who panned or used hydraulic methods would drop mercury, a toxic metal that forms a loose bond with gold, into their sluices. Miners then recovered the resulting mixture of gold and mercury and heated it to separate the two metals. In the process, some of the mercury escaped the sluices and polluted rivers, and some miners became poisoned from breathing in toxic vapors.
Hydraulic mining, meanwhile, eroded landscapes and clogged rivers with debris. In addition to gold and silver, hard-rock lode mining released unwanted metals such as cadmium and arsenic by exposing waste rock to oxygen. It was later discovered that this exposure turned the sulfide in these metals to sulfuric acid, which dissolved the metals and allowed them to leach into water supplies, a process now known as Acid Mine Drainage.
Cyanide and other hazardous chemicals used to separate gold from ore also escaped into the environment, polluting landscapes and killing wildlife. One of the first Coloradans to notice these harmful effects was Edwin Carter, a Breckenridge miner also trained in taxidermy. Carter gave up gold mining in the 1860s and began documenting abnormalities in species caused by mining-related pollution. By 1875 he had accumulated a large collection of specimens at his log cabin home in Breckenridge, which he opened up as a museum for the public, scientists, and naturalists. After his death in 1900, his specimens formed the founding collection of the Denver Museum of Nature and Science. Today, Carter’s cabin at 111 N. Ridge Street remains open to visitors.
Since the 1970s, studies have shown that Peru Creek, one of the tributaries of the Snake River in eastern Summit County, has been heavily contaminated by dissolved metals leaching out of nearby abandoned mines. Since the Snake runs through the popular ski resort town of Keystone—and the resort itself uses its water to make snow—pollution in the watershed threatens both the health of the county’s citizens and the local economy. The Environmental Protection Agency has been monitoring pollution levels in the Snake River since 2009.
As one of the longest-operating mines in the county, the abandoned Pennsylvania Mine is considered the primary contributor to pollution in the Snake River watershed. Parts of the river are so contaminated that they can no longer support aquatic life. The nonprofit Blue River Watershed Group and the Snake River Watershed Task Force, a volunteer environmental group based in Keystone, have coordinated recent efforts to mitigate the effects of mine pollution. The groups also receive support from various partners, including the Keystone Ski Resort and the Colorado Department of Public Health and Environment. Cleanup projects include diverting surface and groundwater away from contaminated mines, moving contaminated rock away from the watershed, and encouraging plant growth on and around contaminated rock.
During the nineteenth century, Summit County was both defined and despoiled by its mines. But in the twentieth century, many local entrepreneurs found that the county’s riches lay atop the mountains instead of underneath them. Norwegian Peter D. Prestrud is credited with starting Summit County’s rich skiing tradition when he built the county’s first ski jump in 1910 near Dillon. But the industry did not officially take off until after World War II, when veterans of the Tenth Mountain Division returned to ski in Summit County. In 1945 the Denver Chamber of Commerce’s Winter Sports Committee hired Tenth Mountain Division veteran Laurence Jump and Olympic skier Frederick Schauffler to survey potential ski areas. They found an ideal site on the west side of Loveland Pass, and added Dick Durrance, another Olympic skier, to help lobby the US Forest Service to declare the site a winter sports area. The Forest Service approved their plans in June 1946, and later that year Arapahoe Basin opened to the public as Summit County’s first ski area.
In the late 1950s, Bill Rounds formed the Summit County Development Corporation. The company opened the Breckenridge Ski Area in December 1961. The resort saw 17,000 skiers in its first year. Multimillion-dollar expansions over the next decade allowed it to accommodate some 271,000 people in 1972. Meanwhile, two other resorts, Keystone and Copper Mountain, opened in 1970 and 1971, respectively. By 2001, the four major ski resorts in Summit County were attracting more than 30 percent of all ski visits in Colorado, and ski tourism made up 37 percent of the county’s economy.
Water Diversion Projects
The mining and ski industries were not the only modern forces reshaping Summit County’s landscape during the twentieth century. Reclamation also left its mark in the form of two major water diversion projects: the Colorado Big-Thompson Project (C-BT), which began in 1938, and the construction of Dillon Reservoir and the Harold D. Roberts Tunnel, which officially began in 1961. Both projects were designed to carry water from Colorado’s Western Slope to the growing metropolis of Denver and farms in eastern Colorado.
The Federal Bureau of Reclamation’s massive C-BT project was approved by President Franklin D. Roosevelt in 1937. One of the most remarkable feats of modern engineering, the project involved the creation of ten reservoirs, eighteen dams, six power plants, and a tunnel boring straight through the Continental Divide. All of these elements would combine to divert a portion of the Colorado River headwaters to the Front Range and eastern Colorado, while also ensuring that the Western Slope retained its agreed-upon share of the precious resource.
Green Mountain Reservoir, on the Blue River in northern Summit County, would hold western Colorado’s share of the diverted water. Green Mountain Dam, the first major piece of the enormous C-BT puzzle, was completed in 1942. In addition to providing recreational opportunities via the newly created reservoir, the dam powers a hydroelectric plant that generates enough electricity to power nearly 60,000 homes.
The idea of damming the Blue River near Dillon had been around since the early 1900s, but it took Denver authorities nearly half a century to finalize plans and acquire the land necessary to create the reservoir, tunnel, and other elements of the project. In 1955 the Denver Water Board met with Dillon residents to hear their concerns. The board offered to compensate residents for having to move their town, but residents still voiced an array of serious concerns, including the loss of property values and tax revenue, as well as overcrowding in local schools caused by an influx of construction workers and their families. The Water Board did its best to bring the city and town to an agreement that would be palatable to both sides, but urban legislators were reluctant to offer much more in the way of compensation and the residents of Dillon were themselves divided over whether to sell their property or make a stand.
By December 1959, however, Dillon’s time was nearly up. The Roberts tunnel was nearing completion and the board sent a letter advising that the town be evacuated by April 1, 1961. Construction on the dam began that year and finished in December 1963. Water began flowing through the Harold Roberts Tunnel on its way to Denver in July 1964. Some residents decided to haul their buildings to staging areas while the new Dillon townsite was developed. But after weighing the considerable risks of moving to the new town, many residents decided to relocate to one of Summit County’s other towns or leave the county altogether.
Although its construction displaced many residents, Dillon Reservoir, or Lake Dillon as it is commonly known today, became an important part of the county’s landscape and economy, adding to its scenic beauty and providing visitors with many recreational opportunities.
Arapaho and White River National Forests
Since 1908, practically all undeveloped land in Summit County has belonged to the federal government as national forests. The Arapaho National Forest, the first national forest in Colorado, was established by President Theodore Roosevelt in 1908. Summit County’s section of the forest was known as the Dillon Ranger District, but by the end of the twentieth century administration had unofficially shifted to calling it the White River National Forest. Congress officially recognized the change in jurisdiction in 1998, transferring stewardship of federal lands in Summit County from the Arapaho National Forest to the White River National Forest.
Today, the Summit County economy relies mostly on tourism. In addition to being the heart of Colorado’s ski country, the county contains five golf courses, two recreation centers, dozens of miles of hiking, skiing, and snowshoeing trails, and one of the state’s largest collections of historic buildings in the Breckenridge Historic District. Anglers are drawn to the Blue River for fly fishing and to the fish-stocked waters of Dillon and Green Mountain Reservoirs, which also offer boating and other aquatic activities. An uptick in tourism in recent years has translated into a boon for Summit County’s coffers: gross revenue from retail transactions increased from $1.6 billion in 2010 to nearly $2 billion in 2014.
Among the current challenges facing Summit County are transit, traffic, and parking in ski towns such as Breckenridge, as well as conservation and climate change in the broader county. While ski tourism continues to be the lifeblood of the county economy today, a string of warmer-than-average winters over the coming years could siphon millions of dollars from the industry. A warmer climate also threatens ongoing efforts to clean up acid mine drainage, as drier streambeds leave more contaminant-holding rocks exposed to weathering processes that result in toxic leaching. Still, the environment remains the county’s most valuable asset, and many residents are committed to helping it remain a stunning draw for locals and tourists alike.