The 'CITY90' layer contains 1990 Census Federal place code boundaries that have been clipped by the county tile outline. The Federal place codes define polygons that are cities or census designated places or are unclassified as to type.

Hydrology representing major hydrologic features digitized from 1:24,000-scale USGS topographic maps.

This dataset provide national land cover data broken into major categories (e.g., urban, forest).

This map is a raster representation of the elevation for the region.

California Department of Transportation roads layer for the study region.