Chief Mountain (Blackfoot: Ninaistako) () is located in the U.S. state of Montana on the eastern border of Glacier National Park and the Blackfeet Indian Reservation. The mountain is one of the most prominent peaks and rock formations along the Rocky Mountain Front, a long overthrust fault, known as the Lewis Overthrust, which extends from central Montana into southern Alberta, Canada. The peak The peak is easily seen from Montana and Alberta due to the rapid altitude gain over the Great Plains which are immediately east of the mountain. Chief Mountain is an example of a klippe. It consists of a Precambrian block which rests directly above much younger Cretaceous gray shales. The 1450-1400 million year old Precambrian rocks are 1300-1400 million years older than the Cretaceous rocks at the base of the mountain. Having an older layer of rock juxtaposed atop younger basement rocks is found on occasion in thrust faults and is commonplace along the Lewis Overthrust which extends from central Montana to far southern Alberta. The surrounding portion of the thrust sheet has been removed by erosion leaving behind this and a few other isolated blocks of Proterozoic rock. Various names Chief Mountain has been a sacred mountain to Native American tribes for hundreds of years. The Blackfoot name for the mountain is Nínaiistáko. The mountain was seen by white explorers in the late 18th century and was known as "Kings Peak" on maps produced in the United Kingdom in 1795. The name was changed in the late 19th century in reflection of Blackfeet naming of the mountain which was "Great Chief". When Glacier National Park was created in 1910, the summit and most prominent eastern slopes of the mountain were located within the park, leaving only the lower slopes within Blackfeet jurisdiction. Chief Mountain remains sacred to many First Nations peoples from both the U.S. and Canada. Natives from all over North America travel to the base of the mountain for sweet grass ceremonies, placing of prayer flags and other religious rites. In the early 1900s as white settlers came to the area, they observed native burial sites scattered along the base of the mountain. Elders from Southern Alberta's Siksika Band (where the Great Chief Crowfoot hailed from) and other First Nation groups have an oral tradition that near the end of days, a Great White God would appear from the top of Chief Mountain and