Durango is a state in Northern Mexico. "The glittering treasure you've been dreaming of day and night lies buried over yonder, beyond that there mountain." --Treasure of the Sierra Madre
Durango is composed of Chihuahuan Desert in the northeast, Altiplano in the central interior, and the Sierra Madre along the western edge of the state. The Sierra Madre of Durango was the setting for the famous B. Traven novel (later adapted into a Hollywood film), the Treasure of the Sierra Madre. One of the great novels about northern Mexico, the book serves as a good introduction to the area to this very day.
Durango is really only now being discovered by tourists. The state has tremendous eco-tourism potential. In many ways the north of the state is very similar to the Copper Canyon area. There are canyons, Mennonites, and Tarahumara. The biggest difference is there are almost no foreign tourists or backpackers here. Which could be good or bad depending on perspective. Less infrastructure and less camaraderie but better opportunity for exploration and interaction with locals.
The city of Durango has been declared a national monument by the Mexican government thanks to over 1000 well-preserved historic buildings, many dating back to the colonial period. Durango is considered to be something of a spa city by many Mexicans because of the many hot springs in the area as well as the natural beauty and wonderful climate the city enjoys. On the down side, the state of Durango is seriously plagued by trouble with the drug cartels, though this very likely won't be an issue for tourists who stay in the city and don't venture into the backcountry.