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thumb|Gold and quartz specimen from the Jib Mine in Basin
Basin is an unincorporated community and census-designated place (CDP) in Jefferson County, Montana, United States. It lies approximately southeast of the Continental Divide in a high narrow canyon along Interstate 15 about halfway between Butte and Helena. Basin Creek flows roughly north to south through Basin and enters the Boulder River on the settlement's south side. As of the 2020 census, Basin had a population of 199.
Archaeologists have discovered evidence of human habitation from 10,000 years ago at a site near Clancy, northeast of Basin. From about 2000 BCE through the mid-19th century, nomadic tribes hunted bison in the grassy valleys that trend east, away from the Rocky Mountains and into the plains. By the time miners found gold in the streams in and near Basin, most of these tribes of Indians had been forced onto reservations by the U.S. government.
Basin rests above the Boulder Batholith, the host rock for many valuable mineral ores found in this part of Montana. After the town became a hub of gold and silver mining, Basin's population peaked at about 1,500 in the first decade of the 20th century but gradually declined as the mines were depleted. Abandoned mining equipment, closed or barricaded mine portals, and the ruins of a smelter and ore concentrator remain in Basin in the 21st century.
Historic buildings from Basin's heyday form much of the core of the CDP's small business district, which includes a fire station, a post office, two restaurants, a bar, a commercial gallery, and small specialty shops. Basin has a small elementary school, its own water system, and a low-power radio station. Local volunteers and elected trustees provide limited services to the settlement, but it relies on the government of Jefferson County for law enforcement and other services. From 1993 through 2011, Basin was home to the Montana Artists Refuge.
Geography and geology
Basin, in Jefferson County, is part of the Helena Micropolitan Statistical Area. It lies at an elevation of above sea level The community is largely surrounded by the Beaverhead-Deerlodge National Forest. No paved roads except the interstate highway, which runs along the river canyon, connect Basin to other towns.
In the late Cretaceous (roughly 81 to 74 million years ago), molten rock (magma) rose to the Earth's surface in and near what later became Jefferson County and eventually formed an intrusive body of granitic rock up to thick and in diameter. This body, known as the Boulder Batholith, extends from Helena to Butte, and is the host rock for the many valuable ores mined in the region. As the granite cooled, it cracked, and hot solutions infiltrated the cracks to form mineral veins bearing gold and other metals. Millions of years later, weathering allowed gold in the veins to wash down to the gravels in Basin Creek, Cataract Creek, and the other creeks near Basin, as well as the Boulder River.
The Basin area is underlain by the quartz monzonite of the Boulder Batholith. The batholith is overlain by dacite from the Paleogene and Neogene periods (roughly 66 million to 1.8 million years ago) and andesite from the late Cretaceous. The andesite and monzonite are cut by dikes of dacite and rhyolite.
History
First peoples
Archeologists think it likely that the first people to live in Montana crossed from Asia to North America over the Bering Land Bridge that existed during the last major Ice Age about 12,000 years ago. Because the middle of the continent was covered with sheets of ice, people who migrated south did so on trails along the edges of glaciers melted by seasonal warming. One such trail, called the Great North Trail, is thought to have followed the Rocky Mountain Front into Montana, passing close to Helena, north of Basin, and continuing into the east-central part of the state. Evidence of these early Paleo-Indians or Clovis people has been found at three sites, one of them the McHaffie site near Clancy about north of Basin. The age of the Clancy artifacts is estimated to be 10,000 years. The Clovis people are thought to have disappeared in about 4,000 to 5,000 BCE when the Montana climate became more dry and would not support the animal populations the Clovis needed to survive.
About 2,000 years ago, a new prehistoric people known as the Late Hunters appeared in Montana, thriving on a bison (buffalo) population living in open grassy areas on the plains and in river valleys. The earliest tribes are thought to have been the Kootenai, who stayed west of the Continental Divide, and the Flathead (Salish), and Pend d'Oreilles, who ventured east of the mountains into and east of the Three Forks country, southeast of Basin. In the 17th century, the Crow entered Montana from the east and the Shoshone from the south. Pressed by other tribes retreating west from white European settlers, the Blackfeet moved into Montana around 1730. Acquiring horses and firearms, and numbering about 15,000, they formed alliances with other incoming tribes, the Assiniboine and the Gros Ventres, and by the mid-18th century dominated the state. When the white explorers Lewis and Clark traveled up the Missouri River to Three Forks, they found only Blackfeet and Blackfeet allies. Heavily dependent on bison, the nomadic life of the Blackfeet "came to an abrupt end in the early 1880s when the buffalo became almost extinct." Prospectors staked claims and built cabins, and within a few years placer mining extended the full lengths of Cataract and Basin Creeks. When a settlement was established in Basin, the buildings at the mouth of Cataract Creek were gradually moved to Basin, and the Cataract camp was abandoned.
Searches for the lode veins on both creeks succeeded by the 1870s and eventually led to significant lode mining at the Eva May, Uncle Sam, Grey Eagle, Hattie Ferguson, and Comet mines in the Cataract Creek district and the Bullion, Hope, and Katy mines in the Basin Creek district. By 1880, the settlement at Basin became the local source of supplies for mines and miners. Despite the ups and downs of the local mines and despite several disastrous fires in town, Basin prospered.
While the smelter sat idle, mining activity continued on the south side of the river in the Hope-Katy mine complex, at the Hope Mill, which crushed and separated ore, and at the Basin Reduction Works. Flumes carried water from upstream on Cataract Creek and Basin Creek to a storage reservoir in town and supplied water to the mills as well as the town's fire hydrants. A separate flume carried water to the mills from upstream on the Boulder River. At the Basin Reduction Works, Corliss steam engines, driven by the coal-fired boilers, provided power to run the mine hoists and the mill machinery, and an electric generator powered by a water wheel made electricity for factory lights and the arc lights at Basin's street intersections. Surplus tailings were discharged into the river and into a dam built for the purpose downstream of Basin.
thumb|right| Former entrance to the Hope-Katy mine complex (2007)The most extensive and successful mining of the Hope-Katy vein began in 1919, when the Jib Consolidated Mining Company began work on the property. When this company acquired the mines, they comprised of workings. Over the next five years, Jib expanded these to more than , and in 1924 the company became the largest gold producer in Montana. In that year, the combined Jib mines produced about of gold, of silver, of copper, and of lead. In 1925, however, the Jib properties passed from the mining company to trustees for creditors, and production declined.
In 1975, the Basin community formed water and sewer districts and, using federal grants to cover about 60 percent of the costs, built a water delivery, sewage, and waste-handling system. By 1990, Interstate 15 had replaced the entire length of U.S. Route 91 in the state. The centerline of the Interstate followed the track of the former Great Northern Railway through town.
Individual mines
Almost opposite the Hope-Katy complex on the south side of the Boulder River in Basin was the Katy Extension Mine on the north side. It produced ore from part of the Hope-Katy lode that had been displaced about to the north by faulting.