Nine Mile Canyon (which is actually 40 miles in length) is located in Utah. Some people refer to it as the world's longest art gallery since there are a lot of panels running the length of the canyon. Although human occupation in this area goes back 12,000 years it is the agricultural Fremont people who are responsible for the huge majority of rock art here. The Fremont people who lived here (AD 500-1300) produced a type of rock art classified as the Fremont Northern San Rafael Style. This style isn't as sophisticated as the Southern Style or as detailed as the Classic Vernal Style. The Northern Style is relatively simple. Anthropomorphs tend to be small and un-ornate. Emphasis tends to be placed on animals rather than people. Fighting and hunting scenes are common since the Fremont people here had to deal with both. Archaic and Basketmaker people left some rock art in the canyon prior to the Fremont.
Farming would have been difficult here and it is assumed that Fremont people located in this area would have supplemented farming with some hunting and gathering. During summers they likely would have farmed in the canyon and in winters they probably would have relocated to higher-elevation forested locations. Very little pottery and household trash has been found around canyon dwellings and this has led anthropologists to assume that they moved around quite a bit.
Large stone buildings and structures were built in Nine Mile Canyon and many of them were built high in difficult to reach areas. They may have been refuge sites as it is believed that various groups moving into the area would have been in potential conflict with the local natives. If conflict erupted, the people of the area could retreat to structures high on the cliffs and come back down once the threat moved on. By 1300 or 1400 AD the people in the canyon had likely been displaced with hunter-gatherer Numic groups like the Utes. These historic Ute people also left some panels in the canyon.
All images taken with a Digital Rebel XT and t1i with various L lenses.