This Level 1 (L1) dataset includes single look complex (SLC) stack products and co-registered interferograms in the HH (horizontal transmit and horizontal receive) polarization for the Atchafalaya Basin, in Southern Louisiana, USA, within the Mississippi River Delta (MRD) floodplain. The data were collected in October 2016 by Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR), a polarimetric L-band synthetic aperture radar flown on the NASA Gulfstream-III aircraft as part of the Pre-Delta-X campaign. A single study region, flight line "gulfco_12011", was sampled six times at approximately 30-minute intervals to monitor changing water levels. The SLC stack product is a standard UAVSAR product delivered by the UAVSAR processing team. The L1 interferograms were generated from the SLC stacks.