Ecoregions denote areas of general similarity in ecosystems and in the type quality, and quantity of environmental resources. The ecoregions shown here have been derived from the "Level III Ecoregions of the continental United States" GIS coverage created by the US Environmental Protection Agency. The useco polygon was converted to a shapefile in ArcToolbox using the "Feature Class To Shapefile" tool. The shapefile was reprojected from Albers Conical Equal Area to Oregon Lambert. The shapefile was clipped to the boundary of Oregon.