The Black Mountain Archaeological Site District demonstrates the potential to yield significant scientific information pertaining to virtually all periods of prehistoric cultural development in the Big Horn Basin of Wyoming, and the Northwest Plains. Cultural components represented in the sites within this district span from early in the Paleoindian Period, perhaps as early as 11,500 years ago, up through the Late Prehistoric Periods, which spans from 1500 to 450 years ago.

No cultural components have been verified from the Early Plains Archaic or Protohistoric Periods. The district includes two large Phosphoria Formation chert quarry areas (48BH1126 and 1127), an open interfluve camp (48BH902), two canyon bottom campsites (48BH901 and 1069) and six rockshelters (48BH900, 1064, 1065, 1067, 1128, and 1129). The Black Mountain and East Spring Creek quarries are representatives of the high-grade Shell Creek Phosphoria sources. The chert from these sources is a fine grained, high quality chert with a distinctive blood red color.

National Register form is available upon request.