Airborne frequency domain electromagnetic (AEM) data were acquired in a grid pattern consisting of many west-east oriented survey lines over the Tallahatchie River during November 2018. Data were collected by members of the U.S. Geological Survey, Crustal Geophysics and Geochemistry Science Center Group, and CGG. AEM data acquired in Leflore County, Mississippi, were collected to characterize the subsurface resistivity structure in support of a U.S. Geological Survey groundwater investigation of the Mississippi Alluvial Plain. Airborne EM data were acquired with the Resolve (CGG Airborne) frequency-domain instrument over the same reach 18 line-kilometers that follow the Tallahatchie River in Leflore County in Mississippi as part of a mapping campaign in the Mississippi alluvial plain region. The AEM data comprise five horizontal coplanar transmitter-receiver (Tx-Rx) coil pairs separated by about 7.9 meters (m) at frequencies between 383 and 133,528 Hertz (Hz), and one vertical coaxial coil pair separated by about 9 m that operates at 3,315 Hz. Nominal system height above ground, or river, surface was 30 m and was recorded along flight paths. Data along the survey line that were used to produce the final resistivity models are provided here. Digital data of the processed soundings are provided, and fields are defined in a data dictionary. (1) File: MAPRegAEM2018_EM_Mag_Rad_rawData_L8072002.csv is comma-delimited ASCII file that contain the least processed data. Data locations are provided as UTM Zone 15 N projection and datum of WGS-84. (2) File: MAPRegAEM2018_ProcessedData_L8072002.csv is comma- delimited ASCII file containing the processed data . Data locations are provided as UTM Zone 15 N projection and datum of WGS-84. (3) File: MAPRegAEM2018_ResistivityModels_L8072002.csv is comma-delimited ASCII files containing the inversion model results. Model locations are provided as UTM Zone 15 N projection and datum of WGS-84. (4) File: 20181115_ShellmoundMS_AEM_LINE120_INVERTED_image.png and 20181115_ShellmoundMS_AEM_LINE120_INVERTED_image.pdf are the inverted model output as a 2D profile of electrical resistivity distribution in the subsurface.