Antelope Canyon is a sandstone slot canyon approximately 30 miles long and about 120 feet (37 m) deep, formed across the ages through water erosion from flash floods, especially during the monsoon season. All of Antelope Canyon is within the Navajo Reservation, in Arizona. Different Navajo families own different sections of the natural slot canyon, and some offer tours that are booked for specific dates and times. Visitors are not permitted to explore the canyon on their own; instead, they must purchase an admission ticket, or a day tour that includes an admission ticket.