Magnetic data collected as part of a high-resolution airborne magnetic and radiometric survey over the region surrounding the Wet Mountains of southern Colorado, including parts of Custer and Fremont Counties, are provided as digital flight-line and grid files. Magnetic surveys measure subtle variations in the Earth’s magnetic field and are sensitive to differences in the magnetic properties of rocks from ground level to many kilometers below. Data for this survey were collected by Sander Geophysics Limited International (SGL) under contract with the USGS. The survey was flown in June and July of 2021 using a helicopter equipped with a magnetometer mounted in a stinger extending from the nose of the aircraft. The helicopter pilots followed pre-planned flight paths in a grid-like pattern, with east-west lines spaced 150 meters apart and north-south lines spaced 1,000 meters apart. A terrain clearance of 80 meters above ground could be realized in areas of low relief, but higher clearances, as much as 200–500 meters, were required over rugged terrain and populated areas for safety reasons. A total of 17,032 kilometers were flown along the lines, covering a 2,200 square-kilometer irregular area. SGL performed extensive data processing after completion of flying and delivered the final data and report in February 2022.