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Ecoregions of North America
For studying plant distribution and ecology, our site emphasizes ecoregions rather than the usual political boundaries like countries, states or provinces, and counties or districts. For North America we use the ecoregions produced by the CEC, which is a collaborative effort of the US EPA, Canada, and Mexico's INEGI. You can find the original data here.
This map shows the level 1 ecoregions, the coarsest level of detail; there are 15 such regions in North America. These are further divided into 50 level 2 regions, 182 level 3 regions, and 967 level 4 regions.
Want to find your region or look up the region of a specific site?
Use our ecoregion locator, or browse our series of maps starting with the map below. If you would prefer, you can also browse by US state. We have not yet generated maps for Mexican states, Canadian provinces, or Alaska, but their regions are searchable in the locator, and you can explore their regions on the master map below.
Region List
This list will help you navigate the regions in case you have problems with viewing or clicking the interactive map above.
| Name | Color on Map | EPA Code |
| Arctic Cordillera | 1.0 | |
| Tundra | 2.0 | |
| Taiga | 3.0 | |
| Hudson Plain | 4.0 | |
| Northern Forests | 5.0 | |
| Northwestern Forested Mountains | 6.0 | |
| Eastern Temperate Forests | 8.0 | |
| Great Plains | 9.0 | |
| North American Deserts | 10.0 | |
| Mediterranean California | 11.0 | |
| Southern Semi-Arid Highlands | 12.0 | |
| Temperate Sierras | 13.0 | |
| Tropical Dry Forests | 14.0 | |
| Tropical Wet Forests | 15.0 | |
| Marine West Coast Forest | 7.0 |
Note that our internal ID scheme is independent of the EPA ID's. This is because the regions stored in our database include both ecoregions and political regions, as well as ecological regions from different countries and different authorities.
We plan to expand this section of our site, allowing you to browse both by ecoregions and political regions (such as states and counties.) We will add more detail over time. Currently we have ecoregion data with four levels of hierarchy for the United States, but only three for the rest of North America. We have articles covering the first and second level regions and have been filling in scattered info on more specific regions, starting in the Mid-Atlantic US where we are located.
