Primary occupation began about AD 1088-1090 by Hisatsinom people closely related to the Chaco Canyon group. They built one of the oldest of the Chacoan Great Houses in the San Juan Valley and one of the largest outlying colonies of Chaco.
The major structures are two stories high, with five to seven large rooms and about 150 smaller rooms. They sit on gravel terraces from the Pleistocene times, and have core-and-veneer masonry walls, T-shaped doorways, and large symmetrically arranged rooms. The builders abandoned the site about 1130.
Intermediate occupation between 1130 and 1185 was by the indigenous peoples of the San Juan Valley and they made no significant structural changes. This is based on the study of trash and ceramics found.
Secondary occupation began in 1185 by people related to Mesa Verde. Some of the Primary building was torn down and changes in the architecture were made. The large rooms were divided and many small kivas were built within the large square and rectangular rooms. The Secondary inhabitants had abandoned this site by 1285, and only a small group remained.
Each of the groups that occupied the site were mainly farmers, and though there was a permanent water supply in the San Juan River, there were many other factors. As each succeeding group moved in they depleted the resources of the area according to their preferences and moved on.
Text from San Juan County Archaeological Research Center's pamphlet "Salmon Ruins & Heritage Park"
and 4 Corners Postcard website.