This dataset consists of 127 wideband and 21 long-period magnetotelluric (MT) stations collected from 2016-2019 across parts of Missouri, Arkansas, Tennessee, Illinois, and Kentucky. The U.S. Geological Survey acquired these data as part of regional investigations into the geologic and tectonic framework of the area and to support mineral resource and geologic hazard investigations. These data have been used to generate a 3D regional conductivity model of the area. Files included in this publication include measured electric- and magnetic-field time series as well as estimated impedance and vertical-magnetic field transfer functions. The data included here are for MT station mrv014 in the Mississippi River Valley survey region. A shapefile with station information for all stations in this dataset is available at https://doi.org/10.5066/P9F7HFH7.