The roughly-corresponding Level I Ecoregion to this ecozone in the United States Environmental Protection Agency's classification, which is also part of the CEC system, is the Northern Forests ecoregion, though that classification includes the woodlands and swamps of northern Michigan and Minnesota, which are adjacent to the Boreal Shield ecozone.

The coastal areas are generally cooler in summer and warmer in winter than the inland regions, with richer soils suitable for farming.

[3] The inland regions are primarily highlands of igneous bedrock with acidic soils that support expansive forests, but are not adaptable to agricultural uses.

[1] The coastal plains are atop sedimentary bedrock, with rich soils suitable for agricultural applications.

[3] This ecozone can be further subdivided into three ecoprovinces:[4] The entire region is relatively cool and moderate during the summer, with mean July temperatures at 18 °C.