Abstract: An airborne radiometric survey of parts of the east flank of the Big Horn Mountains was begun on June 23, and completed on August 27, 1952. An area of approximately 250 square miles was covered, and only two anomalies were found in the entire area. Flight lines were arranged in accordance with the geology of the area, particular attention being given to formations the stratigraphic equivalents of which are known to be uranium bearing in other areas. Two additional zones of radioactivity were found by ground investigation, but assays from both the ground and the airborne discoveries showed no economic uranium deposits.