This dataset provides water surface elevations over the Wax Lake Delta in the Atchafalaya Basin in coastal Louisiana, USA, in May 2015. These Level 2 (L2) data were collected by AirSWOT, an airborne instrument employing near-nadir wide-swath Ka-band radar interferometry to measure water-surface elevation and produce continuous gridded elevation data at 3.6 m resolution. Along with elevation estimates, the dataset includes measures of estimation errors, sensitivity, incidence angle, backscatter, and interferometric correlation. For this application, in situ water level data were added into the AirSWOT phase calibration procedure. These L2 data consist of a set of rasters in Universal Transverse Mercator (UTM) map coordinates for each of the 39 AirSWOT flight lines. These elevation data were later used for calculating elevation and slopes along the main channels in this wetland system, as well as tying observations to ocean tidal conditions.