The Marias Massacre (also known as the Baker Massacre or the Piegan Massacre) was a massacre of Piegan Blackfeet Indians which was committed by the United States Army as part of the Indian Wars. The massacre took place on January 23, 1870, in Montana Territory. Approximately 200 Indians were killed, most of whom were women, children and elderly men.

As part of a campaign to suppress Mountain Chief's band of Piegan Blackfeet, the U.S. Army attacked a different band led by Chief Heavy Runner, to whom the United States government had previously promised their protection. This resulted in public outrage and a long-term shift towards a "Peace Policy" by the Federal Government, as advocated by President Ulysses S. Grant. Grant kept the Bureau of Indian Affairs as a division of the Department of the Interior although the War Department was trying to regain control. He then appointed men recommended by various religious clergyincluding Quakers and Methodistsas Indian agents, in hopes that they would be free of the corruption he had previously found in the department.

Montana ( (listen)) is a state in the Mountain West subregion of the Western United States. It is bordered by Idaho to the west; North Dakota and South Dakota to the east; Wyoming to the south; and by the Canadian provinces of Alberta, British Columbia, and Saskatchewan to the north. It is the fourth-largest state by area, the seventh-least populous state, and the third-least densely populated state. Its state capital is Helena. The western half of Montana contains numerous mountain ranges, while the eastern half is characterized by western prairie terrain and badlands, with smaller mountain ranges found throughout the state. In all, 77 named ranges are part of the Rocky Mountains.

Montana has no official nickname but several unofficial ones, most notably "Big Sky Country", "The Treasure State", "Land of the Shining Mountains", and "The Last Best Place". The economy is primarily based on agriculture, including ranching and cereal grain farming. Other significant economic resources include oil, gas, coal, mining, and lumber. The health care, service, and government sectors are also significant to the state's economy. Montana's fastest-growing sector is tourism; nearly 13 million annual tourists visit Glacier National Park, Yellowstone National Park, Beartooth Highway, Flathead Lake, Big Sky Resort, and other attractions.