These data were compiled to investigate the control of drying on the aeolian transport of river-sourced sand. Objectives of our study were to to examine aeolian sediment transport during a five-day period of low steady river flow on a river sandbar and adjacent aeolian dunefield. These data represent the observed and theoretical threshold fiction velocities for aeolian sediment transport, as well as the grain size, sediment moisture content, surface roughness and other characteristics of the sandbar and sand dune surfaces. These data were collected at a sandbar and aeolian sand dune along the Colorado River approximately 19 km downstream from Glen Canyon Dam at Lees Ferry, Arizona, USA from March 15 to 20, 2021. These data were collected by field observations by the U.S. Geological Survey, Grand Canyon Monitoring and Research Center. These data can be used to investigate the potential for aeolian transport of river-sourced sand.