Floating transient electromagnetic (FloaTEM) data were acquired on the Tallahatchie River during October 2018. During the survey, approximately 18.3 line-kilometers were collected in the Shellmound, Mississippi study area. Data were collected by members of the U.S. Geological Survey, Hydrogeophysics Branch, Lower-Mississippi Gulf Science Center and the Aarhus University HydroGeophysics Group. FloaTEM data acquired along the Tallahatchie River in Leflore County, in Mississippi,were collected to characterize the subsurface resistivity structure in support of a U.S. Geological Survey groundwater investigation of the Mississippi Alluvial Plain. FloaTEM data were collected using an Aarhus University HydroGeophysics Group FloaTEM unit using a transmitter loop (Tx) size, 4 by 2 meter square (m^2), in an offset-loop receiver (Rx) configuration utilizing a receiver coil that is 0.5 by 0.5 m^2 in size (with an effective area of 35 m^2) towed about 7 meters behind the Tx loop. The Tx outputs dual currents of about 3 and 30 amperes (A) for dual-moment transmission. The measurement cycles take approximately 0.5 seconds to complete and are comprised of several hundred individual transients that are averaged into 1D soundings along the profile.. This data release includes the averaged, culled, and inverted FloaTEM data along the survey line that were used to produce the final resistivity models. Digital data of the processed soundings are provided, and fields are defined in a data dictionary.