A generalized streamflow-variability index coverage was created by interpolating a grid (with 6,066-ft^2 cells) from at-site values of the streamflow-variability index computed for 133 rural, unregulated streamflow-gaging stations in Ohio and nearby areas of adjacent states. Grid interpolation was done by means of the interpolate surface routine contained in the Spatial Analyst extension of ArcView. The inverse distance weighting (IDW) algorithm was used based on the 12 nearest neighbors. The streamflow-variability index at a streamflow-gaging station is defined as the standard deviation of the logarithms of the 19 streamflow values at 5-percent class intervals from 5 to 95 percent on the flow-duration curve (Searcy, 1959) of daily mean streamflow for the analysis period. Searcy, J.K., 1959, Flow-duration curves, manual of hydrology-part 2, low-flow techniques: U.S. Geological Survey Water-Supply Paper 1542-A, 33 p.