Question: What Indian reservation that was established in 1868 is located near the Pryor Mountains in Montana?
Context: Dryhead Country is a region in Carbon County and Big Horn County in southern Montana between Bighorn Canyon and the Pryor Mountains.  The locale was named after the piles of dry bison skulls that accumulated at the base of a local buffalo jump.  The Dryhead region starts near the Wyoming border in Bighorn Canyon National Recreation Area and extends northward into the Crow Indian Reservation.  Dryhead Creek drains a portion of the area, falling eastwards into Bighorn Canyon.  The semi-arid basin is one of the most remote areas in Montana.  The area is sparsely populated with isolated ranches. The Pryor Mountain Mustang is a substrain of Mustang considered to be genetically unique and one of the few strains of horses verified by DNA analysis to be descended from the original Colonial Spanish Horses brought to the Americas by the Spanish.  They live on the Pryor Mountains Wild Horse Range located in the Pryor Mountains of Montana and Wyoming in the United States, and are the only Mustang herd remaining in Montana.  They are protected by the Wild and Free-Roaming Horses and Burros Act of 1971 (WFRHBA) and managed by the Bureau of Land Management (BLM), who has set the optimum herd number at 120 animals.  Genetic studies have revealed that the herd exhibits a high degree of genetic diversity and a low degree of inbreeding, and BLM has acknowledged the genetic uniqueness of the herd.  Pryor Mountain Mustangs are relatively small horses, exhibit a natural ambling gait, and domesticated Pryor Mountain Mustangs are known for their strength, sure-footedness and stamina. The Pryor Mountains Wild Horse Range is a refuge for a historically significant herd of free-roaming Mustangs, feral horses colloquially called "wild horses", located in the Pryor Mountains of Montana and Wyoming in the United States.  The range has an area of 39650 acre and was established in 1968 along the Montana–Wyoming border as the first protected refuge dedicated exclusively for Mustangs.  It was the second feral horse refuge in the United States.  About a quarter of the refuge lies within the Bighorn Canyon National Recreation Area.  A group of federal agencies, led by the Bureau of Land Management, administers the range. Mille Lacs Indian Reservation is the popular name for the land-base for the Mille Lacs Band of Ojibwe in Central Minnesota, about 100 miles (160 km) north of Minneapolis-St.  Paul.  The contemporary Mille Lacs Band reservation has significant land holdings in Mille Lacs, Pine, Aitkin and Crow Wing counties, as well as other land holdings in Kanabec, Morrison, and Otter Tail Counties.  Mille Lacs Indian Reservation is also the name of a formal Indian reservation established in 1855.  It is one of the two formal reservations on which the contemporary Mille Lacs Band retains land holdings.  The contemporary Mille Lacs band includes several aboriginal Ojibwe bands and villages, whose members reside in communities throughout central Minnesota. The Pryor Mountains are a mountain range in Carbon and Big Horn counties of Montana.  They are located on the Crow Indian Reservation and the Custer National Forest, and portions of them are on private land.  They lie south of Billings, Montana, and north of Lovell, Wyoming. Pryor Mountains National Forest was established as the Pryor Mountains Forest Reserve by the U.S. Forest Service in Montana on November 6, 1906 by the U.S. Forest Service with 78732 acre .  It became a National Forest on March 4, 1907.  On July 1, 1908 it was combined with part of Yellowstone National Forest to establish Beartooth National Forest.  The name was discontinued. The Crow Indian Reservation (est. 1868) is the homeland of the Crow Tribe of Indians of the State of Montana in the United States.  The reservation is located in parts of Big Horn, Yellowstone, and Treasure counties in southern Montana.  It has a land area of 3,593.56 sq mi (9,307.27 km²) and a total area of 3,606.54 sq mi (9,340.89 km²), making it either the fifth or sixth largest reservation in the country.  (Rankings are switched with the Standing Rock Indian Reservation depending on whether water areas are counted.)  Reservation headquarters are in Crow Agency. The Northern Cheyenne Indian Reservation (Tsėhéstáno in Cheyenne, formerly named the Tongue River Indian Reservation) is home of the federally recognized Northern Cheyenne Tribe.  Located in southeastern Montana, the reservation is approximately 444,000 acres in size and home to approximately 5,000 Cheyenne people.  The tribal and government headquarters are in Lame Deer, which is also the home of the annual Northern Cheyenne Pow wow.  The reservation is bounded on the east by the Tongue River and on the west by the Crow Reservation.  There are small parcels of non-contiguous off-reservation trust lands in Meade County, South Dakota, northeast of the city of Sturgis.  Its timbered ridges that extend into northwestern South Dakota are part of Custer National Forest and it is approximately 40 mi east of the site of the 1876 Battle of the Greasy Grass (known to most Americans as the Battle of the Little Bighorn). Bighorn Canyon National Recreation Area is a national park unit established by an act of Congress on October 15, 1966, following the construction of the Yellowtail Dam by the Bureau of Reclamation.  It straddles the border between Wyoming and Montana.  The dam, named after the famous Crow leader Robert Yellowtail, harnesses the waters of the Bighorn River by turning that variable watercourse into Bighorn Lake.  The lake extends 71 mi through Wyoming and Montana, 55 mi of which lie within the national recreation area.  About one third of the park unit is located on the Crow Indian Reservation.  Nearly one-quarter of the Pryor Mountains Wild Horse Range lies within the Bighorn Canyon National Recreation Area. The Caroline Lockhart Ranch was established in 1926 by Caroline Lockhart, who purchased a 160 acre homestead near Davis Creek at the foot of the Pryor Mountains in Carbon County, Montana while in her fifties.  Lockhart expanded the ranch, adding buildings, land and grazing rights until the ranch comprised about 7000 acre .  The region, known as Dryhead Country, is one of the most isolated places in Montana.
Answer: The Crow Indian Reservation