List of ecoregions in the United States (EPA)

This list provides an overview of United States ecoregions designated by the U.S. Environmental Protection Agency (EPA) and the Commission for Environmental Cooperation (CEC). The CEC was established in 1994 by the member states of Canada, Mexico, and the United States to address regional environmental concerns under the North American Agreement on Environmental Cooperation (NAAEC), the environmental side accord to the North American Free Trade Agreement (NAFTA).

Source: Wikipedia — List of ecoregions in the United States (EPA) (CC BY-SA 4.0)