Northwestern New Mexico has a prodigious number of puebloan ruins dating from the same era as Chaco Canyon, roughly 850 to 1300. One of the notable sites in this number is this nicely-preserved complex along the Animas River near the Colorado border. The exhibits in the visitor center are very informative, and there is a decent film to view as well. Overall, this site makes a great introduction to the Chaco Culture and can be a prequel to a visit to the much more extensive (but much more remote) Chaco Canyon sites.
The site at Aztec Ruins was part of an extensive trade and cultural web that centered on Chaco Canyon and extended hundreds of miles in all directions. There were 400 miles of roads that linked these settlements together, and these people traded for goods as far away as Central America and the Pacific Ocean. The Aztec Ruins (mistakenly named at an earlier time when it was thought that the Aztecs built these structures) are what is left of the largest Ancestral Puebloan community in the Animas River valley. Archaelogical excavations here in the early 1900s yielded thousands of artifacts, including food remnants, tools, clothing, pottery and jewelry. The highlight of the site is the restored great kiva, the circular underground room used for ceremonies and other functions.