The Hopi are a Native American people who primarily live on the 12,635 km² (2,531.773 sq mi) Hopi Reservation in northeastern Arizona. The Hopi Reservation is entirely surrounded by the much larger Navajo Reservation. The two nations used to share the Navajo-Hopi Joint Use Area. The partition of this area, commonly known as Big Mountain, by Acts of Congress in 1974 and 1996, has resulted in seemingly endless controversy.