This is a broad outline of the history of Montana in the United States.
For thousands of years indigenous peoples inhabited what would be Montana. The Louisiana Purchase in 1803 included this land and it was explored during the Lewis and Clark Expedition. The first permanent settlement by Euro-Americans was St. Mary's, established in 1841 near present-day Stevensville. The Montana Territory was established in 1864 and Montana officially became a state on November 8, 1889.
Prehistory Lake Missoula was a prehistoric proglacial lake in western Montana that existed periodically at the end of the last ice age between 15,000 and 13,000 years ago.
Indigenous peoples
Archeological evidence has shown that Paleo-Indians lived in the area beginning more than 12,000 years ago. The oldest dated human burial site in North America was located in 1968 near Wilsall, Montana at what is now known as the Anzick site (named for the discoverers). The human remains of a male infant, found at the Anzick site along with Clovis culture artifacts, establish the earliest known human habitation in what is now Montana. In 2014 a group of scientists released the results of a major project in which they successfully reconstructed the genome of the Anzick boy, providing the first genetic evidence that the Clovis people were descended from Asians, and are related to modern Native Americans. Most indigenous people of the region were nomadic, following the buffalo herds and other game and living by seasonal cycles. Several major tribal groups made their home in and around the land that later became Montana.
The Crow, also known as the Apsáalooke, were the first of the native nations currently living in Montana to arrive in the region. Around 1700 AD they moved from Alberta to south-central Montana and northern Wyoming. In the 19th century, Crow warriors were allies and scouts for the United States ArmyRobert H. Lowie, The Crow Indians (U. of Nebraska Press, 1983) The modern Crow Indian Reservation is Montana's largest reservation, located in southeastern Montana along the Big Horn River, in the vicinity of Hardin, Montana.
The Cheyenne have a reservation in the southeastern portion of the state, east and adjacent to the Crow. The Cheyenne language is part of the larger Algonquian language group, but it is one of the few Plains Algonquian languages to have developed tonal characteristics. The closest linguistic relatives of the Cheyenne language are Arapaho and Ojibwa. Little is known about the Cheyenne people before the 16th century when they were first recorded in European explorers' and traders' accounts.E. Adamson Hoebel, The Cheyennes: Indians of the Great Plains (1978)
The Blackfeet reservation today is located in northern Montana adjacent to Glacier National Park. Prior to the reservation era, the Blackfoot were fiercely independent and highly successful warriors whose territory stretched from the North Saskatchewan River along what is now Edmonton, Alberta in Canada, to the Yellowstone River of Montana, and from the Rocky Mountains east to the Saskatchewan River. Their nation consisted of three main branches, the Piegan, the Blood, and the Siksika. In the summer, they lived a nomadic, hunting lifestyle, and in the winter, the Blackfeet people lived in various winter camps dispersed perhaps a day's march apart along a wooded river valley. They did not move camp in winter unless food for the people and horses or firewood became depleted.William L. Bryan, Montana's Indians: Yesterday and Today (1995)
The Assiniboine also known by the Ojibwe exonym Asiniibwaan ("Stone Sioux"), today live on the Fort Peck Indian Reservation in Northeastern Montana shared with a branch of the Sioux nation. Intermarriage has led to some of the people now identifying as "Assiniboine Sioux". Prior to the reservation era, they inhabited the Northern Great Plains area of North America, specifically present-day Montana and parts of Saskatchewan, Alberta and southwestern Manitoba around the US/Canada border. They were well known throughout much of the late 18th and early 19th centuries. Images of Assiniboine people were painted by such 19th-century artists as Karl Bodmer and George Catlin. The Assiniboine have many similarities to the Lakota Sioux in lifestyle, language, and cultural habits. They are considered a band of the Nakoda, or middle division of the Sioux nation. Pooling their research, historians, linguists and anthropologists have concluded the Assiniboine broke away from the Lakota and Dakota Sioux bands in the 17th century.
The Gros Ventre are located today in north-central Montana and govern the Fort Belknap Indian Reservation. Gros Ventre, meaning "Big Bellies" in French, is a name of unknown origin. The people call themselves (autonym) A'ani or A'aninin (white clay people), perhaps related to natural physical formations. They were called the Atsina by the Assiniboine. The Ajani has 3,682 members and they share Fort Belknap Indian Reservation with the Assiniboine, though the two were traditional enemies. The Ajani is classified as a band of Arapaho; they speak a variant of Arapaho called Gros Ventre or Atsina.
The Kootenai people live west of the Continental Divide. The Kootenai name is also spelled Kutenai or Ktunaxa . They are one of three tribes of the Confederated Salish and Kootenai Tribes of the Flathead Nation in Montana, and they form the Ktunaxa Nation in British Columbia, Canada. There are also Kootenai populations in Idaho and Washington. The Salish and Pend Oreilles people also live on the Flathead Indian Reservation. The smaller Pend d'Oreille and Kalispell tribes originally lived around Flathead Lake and the western mountains, respectively.
The territories of the different tribes were defined by multiple and varied treaties with the United States, generally shrinking their land boundaries with each revision.Kappler, Charles J.: Indian Affairs. Laws and Treaties. Vol. 2. Washington, 1904.
The Ojibwe and Cree people today jointly share the Rocky Boy's Reservation in north-central Montana. Rocky Boy's reservation was created after most of the others as a home for some of the "landless" tribes who did not obtain reservation lands elsewhere. The creation of the reservation was largely due to the efforts of the Chippewa leader Stone Child (aka "Rocky Boy"). The Little Shell Chippewa also have a presence in Montana, however they do not have a reservation.
Other native people had a significant presence in Montana, though today do not have a reservation within the state. These nations included the Lakota, the Arapaho, and the Shoshone. The Kiowa and the Kiowa-Apache claim an early history in the late 17th century) as nomadic hunters between the Yellowstone and Missouri.Boyd, Maurice: Kiowa Voices. Ceremonial Dance, Ritual and Song. Part I. Fort Worth, 1981. pp. 6 and 10.
Louisiana Purchase
On April 30, 1803, the Louisiana Purchase Treaty was signed by representatives of the U.S. at Paris, France. The United States Senate ratified the treaty on October 20 and President Thomas Jefferson announced the treaty to the American people on July 4, 1803. The area covered by the purchase included much of the present-day United States between the Continental Divide and the Mississippi River, encompassing the Great Plains including part of what is now Montana, particularly the Missouri River drainage. The rights to the Louisiana Purchase territory cost the U.S. $15 million, which came out to an average of 3 cents an acre. On March 10, 1804, a formal ceremony was conducted in St. Louis, Missouri, to transfer ownership of the territory from France to the United States of America. The lands of present-day Montana were practically unknown and too distant from the seats of power for this political boundary change to have much impact upon them, but the Louisiana Purchase would prove a sea-change for the area.
Lewis and Clark Expedition
The Louisiana Purchase sparked interest in knowing the character of the lands the nation had purchased, including their flora and fauna and the peoples who inhabited them. President Thomas Jefferson, an advocate of exploration and scientific inquiry, had the Congress appropriate $2,500 for an expedition up the Missouri River and down the Columbia River to the Pacific Ocean. He had envisioned an expedition of this nature since at least the early 1790s, due to his driving interest to secure a route for the U.S. to trade interests on the Pacific coast. Jefferson tapped his personal secretary, Meriwether Lewis, to lead the expedition, and Lewis recruited William Clark, an experienced soldier and frontiersman who became an equal co-leader of the Lewis and Clark Expedition. They were to study, map and record information on the native people, natural history, geology, terrain, and river systems. The expedition floated up the Missouri River, making winter camp near the Mandan villages, east of the present border of Montana and North Dakota. The following spring, the Corps of Discovery ascended to the headwaters of the Missouri River, obtained horses from the Shoshone people to cross the Continental Divide, eventually floating down the Columbia River to the Pacific Ocean.
On the return trip heading east through present-day Montana, in July 1806, after again crossing the Continental Divide, the Corps split into two groups so Lewis could explore and map the Marias River and Clark could do the same on the Yellowstone River. While proceeding down the Yellowstone, Clark signed his name northeast of modern-day Billings. The inscription consists of his signature and the date July 25, 1806. Clark named the pillar after Jean Baptiste Charbonneau, nicknamed "Pompy", the son of Sacagawea, a Shoshone woman who had helped to guide the expedition and, along with her husband Toussaint Charbonneau, had acted as an interpreter. Clark's inscription is the only remaining physical evidence found along the route that was followed by the expedition. In the meantime, Lewis' group descending the Marias met a small party of Piegan Blackfeet. Their initial meeting was cordial, but during the night, the Blackfeet tried to steal their weapons. In the ensuing struggle, two men were killed, the only native deaths attributable to the expedition. To prevent further bloodshed, the group of four—Lewis, Drouillard, and the two Field brothers—fled over in a day before they camped again. Lewis's and Clark's separate parties rejoined one another at the confluence of the Yellowstone and Missouri rivers on August 12, 1806. Thus reunited, and heading downstream, they were able to quickly return to St. Louis. During the trip, the expedition spent more of its time in what today is Montana than any other place.
First settlements
St. Mary's Mission was the first permanent European settlement in Montana. Through interactions with Iroquois between 1812 and 1820, the Salish people learned about Christianity and the Jesuit missionaries (known as "blackrobes"), who worked with Native tribes teaching about agriculture, medicine, and religion. Interest in these "blackrobes" grew among the Salish. In 1831, four young Salish men were dispatched to St. Louis, Missouri to request a "blackrobe" to return with them to their homeland in the Bitterroot Valley. The four Salish men were directed to the home and office of William Clark (of Lewis and Clark fame) to make their request. At that time Clark was in charge of administering the territory they called home. Through the perils of their trip, two died at the home of General Clark. The remaining two secured a visit with St. Louis Bishop Joseph Rosati, who assured them that missionaries would be sent to the Bitterroot Valley when funds and missionaries were available in the future.