The buttes standing over this valley are the eroded remnants of a plateau that once buried them entirely; what remains is roughly a tenth of the rock that was here fifty million years ago. Wind and water took the rest. The De Chelly sandstone that forms the upper walls was laid down as desert dune fields in the Permian, then capped by the harder Shinarump conglomerate that now protects each summit like a lid. The Navajo call the place Tsé Bii' Ndzisgaii, the valley of the rocks. It sits within the Navajo Nation and has been under tribal park administration since 1958, the first park established by a sovereign Native nation in the United States. That governance is not incidental. It is why a monument valley backcountry jeep tour reaches ground that self-drive visitors never see. The seventeen-mile loop road is open to all vehicles; the restricted backcountry beyond it — Mystery Valley, the arches, the hogans, the petroglyph panels — may only be entered with an authorised Navajo guide. Commercial photography arrived early. John Ford filmed Stagecoach here in 1939 and returned repeatedly, and the resulting silhouettes of the Mittens and Merrick Butte became the visual grammar of the American West for audiences who had never crossed the Mississippi. The valley's fame is therefore partly borrowed and partly geological accident. Long before either, Ancestral Puebloan communities built masonry structures beneath the overhangs and left handprints and spiral petroglyphs on the sandstone; several of those sites remain on the backcountry routes. The rock itself explains the colour. Iron oxide in the sandstone produces the red; manganese and desert varnish darken the vertical faces where seasonal water drains. Elephant Butte, the Three Sisters, Totem Pole and the Yei Bi Chei formation each register differently as the sun moves, which is why a monument valley backcountry jeep tour tour is timed rather than merely routed. Sunrise and sunset departures exist because the light, not the itinerary, is the variable. What the tribal park protects today is also inhabited. Families still hold grazing rights inside the valley and live in dwellings scattered across the sand, and guides on these Monument Valley landmarks routes are frequently describing their own family's ground. Access to the park requires the Navajo Nation conservation fee of 8 USD per person, per day, collected at the gate on Monument Valley Road. Entry hours run 06:00–20:00 daily. Beyond that gate, the difference between looking at the valley and being taken through it is a matter of permission, and permission is granted person to person.