Description: The data are derived from precipitation gauge station point data from across Marin County, including the Marin OneRain network (primary source), as well as selected data from National Centers for Environmental Information (NCEI) and NOAA Atlas 14. The 1-year, 1-hour rainfall depth is defined as the 1-hour rainfall accumulation that is expected to be equaled or exceeded an average of once per year. The 1-year, 1-hour rainfall depths for the OneRain and candidate NCEI rain gauges were computed using an algorithm developed by Dubin Environmental for this project; NOAA Atlas 14 rainfall statistics were downloaded directly from the Precipitation Frequency Data Server. The rainfall depth point data were interpolated across the County using the Empirical Bayesian Kriging method. The distance from a location to rain gauges, along with raster layers of mean annual precipitation and elevation as correlation variables, were inputs to the Kriging analysis that estimated the 1-year, 1-hour rainfall depths across the County as a raster layer produced with 500-foot pixels. The rainfall depths vary from 0.50 inches to more than 0.85 inches, with a distribution that is consistent with the values computed from the rain gauge data and mean annual rainfall values. The raster data pixels were converted to polygons with no smoothing, and the 1-year, 1-hour rainfall depth values were rounded to 2 decimal places. The polygons were dissolved on the rainfall depth value to group adjacent cells with the same value and reduce the total number of polygons to produce this dataset. The data are intended to support design calculations for full trash capture bioretention systems. Project designers can look up project location-specific 1-year, 1-hour rainfall depths, and then use these depths for bioretention sizing calculations. Data users may request a copy of the original raster dataset (32 bit floating point GeoTIFF) by contacting MCSTOPPP at mcstoppp@marincounty.gov .