This dataset contains drainage basin boundaries for 253 U.S. Geological Survey (USGS) streamgages in Alaska that had at least 5 years of daily streamflow through September 30, 2017, three of which were delineated for alternate basin conditions. This compilation includes selected boundaries produced in 2014 (https://doi.org/10.5066/P143KNEJ). Additional basin boundaries were delineated from the streamgage location to the nearest USGS Watershed Boundary Dataset (WBD) HUC boundary and along HUC boundaries from that intersection to the basin headwaters. Streamgages selected for drainage basin delineation included streamgages in Alaska that met selection criteria for a statewide study of seasonal flow regimes (Curran and Biles, 2021). Sites for that study included USGS streamgages that had at least 5 years of daily streamflow that responded mostly to seasonal meteorological inputs, that had a definable drainage basin above a minimum size from which basin characteristics could be determined, and that provided streamflow data not similar to another streamgage record in the dataset. For three streamgages, the drainage basin boundary was delineated for the drainage area associated with regulated (diverted) or unregulated streamflow conditions contemporaneous with a period of streamflow record other than the present. Selected basins were previously published in the WBD as "NWISDrainageArea" features.