You searched for: Author United States. Environmental Protection Agency Remove constraint Author: United States. Environmental Protection Agency Subject Biology and Ecology Remove constraint Subject: Biology and Ecology Subject Ecological regions Remove constraint Subject: Ecological regions Place Delaware Remove constraint Place: Delaware
2003. United States. Environmental Protection Agency. This polygon shapefile shows Omernik's Level III ecoregions, derived from a 1:7,500,000 map created by J.M. Omernik in 1987 and from refinements of... National Atlas of the United States.