The U.S. Army Corps of Engineers' Upper Mississippi River Restoration (UMRR) program, through its Long Term Resource Monitoring (LTRM) element, collected aerial imagery of the systemic Upper Mississippi River System (UMRS) during the summer of 2020. A Land Cover/Land Use (LCU) spatial database was developed based on the 2020 aerial imagery, which adds a fourth systemic-wide database to the existing 1989, 2000, and 2010/11 LCU databases. These data have been used to create a variety of products, one of which is a data set used to classify aquatic areas. The 2020 aquatic areas data sets were created by first generalizing the available land cover/use data into a land/water data set, then reinterpreting the areas classified as water to determine the type of aquatic area. This level 1 aquatic areas data set was then further modified to produce the level 2 aquatic areas data set. The intent of the second level classification is to further distinguish geomorphic features not easily interpreted visually. Bathymetric and land cover data, automated approaches, and imagery layers were used to reclassify select level 1 classes for level 2. The Contiguous Floodplain Shallow Aquatic and Contiguous Impounded classes were reclassified to Contiguous Floodplain Lake and Side Channel. Existing and newly delineated Side Channels were further classified into Side Channels and Tertiary Channels. Area coverage for this data set is the Upper Mississippi River floodplain between Minneapolis, MN and Cairo, IL, and the Illinois River floodplain from its confluence with the Mississippi to Joliet, IL.