Floodplain inundation is believed to be the dominant physical driver of an array of ecosystem patterns and processes in the Upper Mississippi River System (UMRS). Here, we present the results of a geospatial surface-water connectivity model in support of ecological investigations fully described in the USGS Open File Report entitled “Indicators of Ecosystem Structure and Function for the Upper Mississippi River System” (De Jager et al., in review). Briefly, we identified likely instances of floodplain submergence by comparing a daily time series of gage-derived water surface elevations to topo-bathymetric data modified to account for slopes and hydrologic routing. The resulting raster attribute table contains columns for unique characterizations of surface water inundation dynamics (including measures of event frequency, duration, depth, and timing), yearly sums of the number of days a surface was inundated, and a classification of floodplain areas based on average annual duration values. All calculations summarize patterns occurring during 1 April – 30 September from 1972 to 2011. We excluded areas permanently wetted (aquatic areas), surfaces in agricultural production, roads, and developed areas. The data are intended for use in geospatial analyses of UMRS floodplain ecosystem patterns and processes.