The property illustrates the extreme conditions of altitude, climate, and isolation faced by mining operations in the area. 

Dating to the 1930s, the Crescent Moly Mine #100 and Mining Camp are associated with the Molybdenum boom and the Climax mine phenomenon.

The Gold Prince Mine, Mill, and Aerial Tramway is a representative large-scale industrial mining and milling complex from the principal period of hard-rock mining in Colorado.

The Lebanon Tunnel was driven into Republican Mountain by the Lebanon Mining company in 1870.

Located in the Pine Creek mining district, structures in the complex include a cabin, a burro shed/bunk house, a forge, and several related outbuildings.  All date from the 1880s and are constructed of hand hewn logs with A and V joints.  Low pitch gabled roofs were made of logs, mud, dirt, and grass.

In 1879, the Smuggler was among the first strikes made by Charles Bennett when he and other Leadville miners first came to the Roaring Fork Valley, and the Smuggler Mining Company was incorporated in November 1881. 

Begun in 1893, the Argo Tunnel extends approximately five miles toward Central City at an average depth of 1,800 feet.

The 1901 Cardinal Mill is significant for engineering and industry as an outstanding example of a concentration facility as defined in the Mining Industry in Colorado Multiple Property Listing, and Amendment to Metal Mining and Tourist-Era Resources of Boulder County Multiple Property Documentation Form (MPDF).  The mill was important to western Boulder County, contributing to a highly productive tungsten ore operation until 1942. 

The complex includes a 150-ton flotation mill, the mine tunnel, several associated buildings, and the ruins of several buildings that were destroyed by the county's deadliest avalanche in 1929.

The Independence Mine and Mill is located on the south slope of Battle Mountain at an altitude of approximately 9,780 feet.  In 1891, Winfield Scott Stratton made the first major strike of gold in the Cripple Creek/Victor area.  The most intensive period of development of the mine coincided with the repeal of the Sherman Silver Purchase Act and the restoration of the gold standard of currency.  

Located on Republican Mountain, midway between Georgetown and Silver Plume, the facility was a key component in the early development and prosperity of Georgetown. 

The circa 1890 Modoc Mill is a good example of industrial architecture associated with Boulder County’s mining history.  This concentration mill of wood and metal reaches four stories in height.  The uppermost story of hewn logs received the ore.  Here gravity bins held the ore until it was fed into a crusher and the stamping apparatus below. 

The Paris Mill is significant in the area of industry, engineering and architecture, from 1895 when it first opened, to 1937, when mill operations ceased. The facility was instrumental in the success of the greater Paris Mine, a major gold producer important to western Park County. 

The Rocky Mountain Mammoth Mine is significant for its association with the mining industry in the mountains of Boulder County.  As a telluride gold ore producing mine, the Rocky Mountain Mammoth contributed to a major mining revival experienced in the Magnolia Mining district and elsewhere in Boulder County in the late 1890s and early 1900s.

The 1920 Valley View Leasing and Mining Company Mill, commonly known as the Matterhorn Mill, is listed on the National Register of Historic Places under Criterion A in the area of industry at the local level of significance for its contribution to the 20th-century silver mining in Colorado's San Juan Mountains where it related directly to mining within San Bernardo Mountain.  When constructed the Matterhorn Mill was a state-of-the-art flotation mill that utilized new technology to produce a higher grade concentrate than could be accomplished by the old-style stamp mill with concentration (s

From 1891 to 1893, this smelting facility, also known as the Holden Lixiviation Works, played a significant role in the production of silver during Aspen’s silver mining boom. p

Completed in 1917, the brick and tile smokestack reaches a height of 365 feet.  Its concrete foundation extends 30 feet into the ground.

The 1883 Fox Mine Office Building is associated with coal mining in the Marshall area. 

Although a large rambling, log and wood frame building on the approximately 8½-acre site dates from earlier ranching operations, the property primarily reflects its association with the mining activities occurring there from 1906 to 1923.  Ditches, ponds, and tailings piles continue to dot the landscape.

Originally built as a two-story residence in 1878, a third floor was added in 1888. 

Nearly square in plan, with a steeply pitched hip roof, the house was built with enough rooms to accommodate coal miners as boarders, a common practice which helped supplement the owner’s income.  

In 1900, the large two-story Lafayette House opened its doors for business, accepting both overnight guests and boarders. 

One of the original miner’s homes constructed in the 1890s at the Gladstone Mine near Lafayette, it was moved to its present site after the start of the strike in 1910.

The Martin Mining Complex is associated with the mining industry in the San Juan Mountains and the Eureka Mining District.  The complex displays the development of industrialized hard rock mining and the transportation infrastructure needed to make such mining profitable in a rugged region.  The Martin Mining Complex is representative of the boom and bust cycle that was always present with industrialized mining.  The 1929 Martin Boardinghouse is one of the best-preserved and largest boardinghouses still standing in the San Juan Mountains.  More precisely, the Martin Boardinghouse can be cal

Constructed circa 1888, the house is associated with Mary Miller, the founder of the town of Lafayette.  In 1884, coal was discovered on the 1280 acre Miller farm.

The circa 1904 -1910 Minnie Gulch Cabins site, including the cabins, dugout, and associated artifact scatters, represent a typical small residential and industrial complex associated with nearby mining during the turn of the 20th Century.  Intact groupings of this sort from the hard-rock mining period in Colorado are unusual. 

The circa 1905 Placer Gulch Boarding House is a rare surviving example of a 1½ story boarding house from the hard-rock mining era in Colorado’s San Juan Mountains.  The building originally had private living quarters, a kitchen, dining room and large storage room on the first floor with benches and individual beds on the second.  An adit to the Prospect Mine is just down the slope from the boarding house and the Gold Prince aerial tramway passes through this site. 

The inn originally functioned as part of the model community built by John C. Osgood for the workers associated with his nearby coke producing and coal mining operations.

Situated in the heart of the San Juan Mountains, Animas Forks is a historic abandoned mining town established in 1875.

Although little remains today, the camp site is representative of the boom and bust cycles typical of many Colorado mining communities.  With a history paralleling the Tellurium / White Cross Mining Camp, it was never formally platted as a town site. 

The site consists of four recognizable cabin ruins that were built starting in approximately 1879 in answer to a promising silver strike. 

The cluster of log cabins and cabin ruins remaining on the site are associated with early mining history in the Upper Roaring Fork area of eastern Pitkin County.

Little Rome is the site of an historic mining camp that was occupied by Italian immigrants who worked at the Ute-Ulay Mine and Mill from 1889 to 1899.

A silver strike in 1879 prompted the arrival of prospectors and entrepreneurs such as Benjamin F. Burnett and William Baker from Fort Collins.  They organized the Middle Park and Grand River Land Improvement Company for the purpose of establishing Lulu City, which was named for Burnett’s daughter. 

The 40-acre parcel comprises the site of the Ludlow tent colony and represents the event known as the Ludlow Massacre.  

Although little remains today, the camp site is representative of the boom and bust cycles typical of many Colorado mining communities.

Located eight miles from the Arkansas River, the camp is associated with early mining history in the Clear Creek Canyon area.

The townsite is significant as the remains of a prosperous Roaring Fork Valley mining camp of the 1880s. Originally known as Castle Forks, the town of Ashcroft was incorporated in 1882. Its peak population of approximately 1,000 supported a variety of commercial enterprises.

Located in the Rocky Mountains approximately 100 miles west of Denver, Breckenridge is an example of a mining boom town that experienced a new era of prosperity as a result of the post World War II boom in the ski industry.  Settlement in the area began in 1859.  

Were it not for the discovery of gold in 1859, there is hardly a more unlikely location for the establishment of a "boomtown" than the rugged and inhospitable terrain of the surrounding mountainsides.  

Cokedale is a significant example of a company-owned coal camp and is associated with the coal mining and coke industry that served as the predominant basis of the southern Colorado economy around 1900.  While most similar coal camps were dismantled as mines ceased operation in the Las Animas-Huerfano district beginning after World War I, Cokedale continued to thrive as a company town until 1946.  

Settlers looking for precious metals were in the area as early as 1874.  As the number of mining camps grew, Crested Butte thrived as a supply center, and the town was incorporated in 1880.  As the gold and silver played out, the mining of nearby high quality bituminous coal supported the economy.  The Colorado Fuel and Iron Company and its predecessors developed coal mines and coke ovens, making the Crested Butte area the state’s leading mountain coal operation by 1882.

The Cripple Creek mining district, originally pronounced worthless by mining experts, produced an estimated $400,000,000 in gold.  At its peak, there were over five hundred mines.

The district consists of 86 contributing buildings which collectively reflect the late 19th- and early 20th century history and architecture of the downtown area.  Since its founding in the early 1880s, with the arrival of the railroad, Durango grew first as a mining supply and smelter center.  It soon became a focal point for agriculture and logging in southwestern Colorado. 

In 1880, Durango was platted by employees of General William Jackson Palmer of the Denver Rio Grande Railroad.  East 3rd Avenue, known prior to 1893 as the "Boulevard", remains a prestigious residential area located along the bluffs overlooking the downtown commercial district.

The district includes surviving examples of the Pioneer Log, Commercial Vernacular, and Rustic Tourist building traditions associated with the mountainous portion of Boulder County.  

Prior to the Leadville strike of 1878, the district was the most important silver camp in Colorado.  The initial boom period dates from the discovery of gold by George and David Griffith in 1859. 

Organized in 1859, Gold Hill was one of Colorado’s earliest mining camps and remains an excellent example of the pattern of settlement and community development within the 19th century metal mining communities of Boulder County. 

The simple two-story wood frame building has a flat roof.  The community erected the building in 1899.  By 1900, Goldfield was the third largest town in the booming Cripple Creek mining district. 

The district has been the commercial center of the community since its development in the late 19th century. clear

Established in 1875 as a supply center for the heavy mining activity in the area, people found their way to Lake City via the Saguache-San Juan Toll Road built by Enos Hotchkiss, one of the town founders.

The district encompasses a scattered collection of architecturally distinctive and historically important masonry buildings supported by numerous residential and commercial buildings that contribute to the overall appearance associated with late 19th century western mining towns. 

Located in the San Juan mountains, the district encompasses almost the entire historic townsite and reflects Ouray’s importance as a supply center for the nearby mining regions from 1886 to 1915

St. Elmo owes its existence to the development of silver mining, which began in the Chalk Creek area in the 1870s.  Originally platted as Forest City, its brief era of prosperity occurred during the 1880s with the coming of the Denver South Park & Pacific and the Denver & Rio Grande railroads.

The Redstone Historic District is a rare, intact Colorado example of an industrial company town, with examples of buildings ranging from worker’s cottages to the large estate of the industrial magnate John Cleveland Osgood.

The town is situated at the center of the San Juan mining district.  Prospecting began in the 1860s, but it was not until 1871 that the first profitable silver vein was discovered in nearby Arrastra Gulch.  The late 19th and early 20th century residential and institutional buildings within the district reflect the prosperity brought about by one of Colorado’s richest mineral producing regions.  

The district encompasses most of the original town and is significant for its association with the settlement of the western frontier and the development of metal mining. 

The district contains many relatively unaltered and contiguous commercial, public, fraternal and religious buildings of late 19th and early 20th century design.  They form the commercial core of an important mining community that composed part of the Cripple Creek-Victor Mining District. 

Located four miles further into Clear Creek Canyon than the Vicksburg Mining Camp, the property is important for its association with early mining history in the area.