Digital aerial photographs of the Buffalo National River in northern Arkansas were acquired on August 24, 2021 to support research on remote sensing of benthic algae. The images included in this data release were obtained by the U.S. Fish and Wildlife Service using the following key pieces of equipment: Quest Kodiak K100 aircraft, PhaseOne iXURS-1000 4-band (RGB and NIR) 100 mega-pixel medium format digital camera, SOMAG gyro-stabilized/vibration isolation sensor mounting, and POS AV510 GNSS/IMU navigational system. The original images were processed using photogrammetry software to generate orthophotos for the entire project area, delivered as GeoTIFF tiles. The tiles covering each of the two primary study reaches were identified and combined into a separate mosaic for each reach using ArcMap GIS software. This data release includes a comma-delimited (*.csv) text file with a listing of the orthophoto mosaics with columns: River, Reach, AcquisitionDate, Sensor, PixelSizeMeters, Projection, Datum, and ImageFileName. The images are provided as GeoTIFF files with an embedded header that includes spatial referencing information. The map projection and datum for these data are UTM Zone 15 N and WGS84, respectively. This image data set was used to produce spectrally based depth estimates and classifications of benthic algal coverage.