As noted above, the Pawnee were subjected to continual raids by Lakota from the north and west. On one such raid, 5 August 1873, a Sioux war party of over 1,000 warriors ambushed a Pawnee hunting party of 350 men, women, and children. The Pawnee had gained permission to leave the reservation and hunt buffalo. About 70 Pawnee were killed in this attack, which occurred in a canyon in present-day Hitchcock County. The site is known as Massacre Canyon. Because of the ongoing hostilities with the Sioux and encroachment from American settlers to the south and east, the Pawnee decided to leave their Nebraska reservation in the 1870s and settle on a new reservation in Indian Territory, located in what is today Oklahoma.