This dataset includes a shapefile representing river valley bottoms for the Chesapeake Bay watershed (CBW) and Delaware River basin (DRB), and tabular data summarizing river valley confinement for each local National Hydrography Dataset Plus High Resolution (NHDPlusHR) catchment and the upstream area weighted, average accumulation for each catchment. The river valley bottom file was generated from 1/3rd arc-second (~10-meter) Digital Elevation Models (DEMs) and NHDPlusHR flowlines using the Valley Confinement Algorithm (Nagel and others, 2014) developed by the U.S. Forest Service Rocky Mountain Research Station. The degree of local catchment valley confinement is defined as the percentage of the NHDPlusHR flowline that does not intersect with the mapped river valley bottom and the upstream accumulated value is calculated as the upstream area weighted average. The tabular data are provided as both a csv and parquet file.