The temperate deciduous forest biome occupies most of the eastern part of the United States and a small strip of southern Ontario.
Frost occurs throughout the biome, and summer and winter are distinct seasons.
The dominant plant species of the biome are broad-leaved deciduous trees. Because the biome covers such a large geographical area, large differences have led to the recognition of eight major forest regions within the biome, each dominated by a different species or association of species. The mixed mesophytic forest region is in the centrally located and topographically diverse Appalachian and Cumberland Plateaus. Geologically, it is the oldest region in the biome and is the most complex and highly developed biotically. Nearly all the dominant species in the entire biome are found here, and many reach their maximum development here.