The U.S. Geological Survey (USGS) collected magnetic susceptibility measurements on rock outcrops to help understand causative sources of magnetic survey anomalies in the Silverton caldera region, southwest Colorado. A total of 1,400 measurements of magnetic susceptibility from 87 locations have been conducted on Paleogene volcanic and plutonic rocks that have been hydrothermally altered. Magnetic susceptibility measurements were taken using an SM30 handheld instrument manufactured by ZH Instruments. The measurements aid in understanding the geology and potential mineral resources in the Silverton caldera. Previously mapped lithologies and alteration assemblages were used to guide measurement locations. Multiple measurements were made at each location to help understand the magnetic susceptibility variation at each outcrop and sample lithology and alteration units were derived from existing USGS geologic maps noted in the supplemental information section of the metadata file. Sample locations were determined using handheld Global Position System units.