This dataset contains base-flow recession time constant (tau) contours that are interpreted from tau values calculated at streamgages in the Niobrara National Scenic River study area. The contours were created by interpolating the calculated tau values using geostatistical kriging methods. Kriging is a geostatistical method that can be used to determine optimal weights for measurements at sampled locations (streamgages) for the estimation of values at unsampled locations (ungaged sites). The kriged tau map could be used (1) as the basis for identifying areas with different hydrologic responsiveness, and (2) in the development of regional low-flow regression equations. The Geostatistical Analyst tools in ArcGIS Pro version 2.5.2 (Environmental Systems Research Institute, 2012) were used to create the kriged tau map and perform cross validation to determine the root mean square error (RMSE) of the tau map. The results of the kriging were then exported from ArcGIS to contours.