American Dagger Moths inhabit woodlands along the eastern United States and Canada, especially areas with a high degree of moisture in the soil, such as swamps and mesic forests. The young live on trees and eat their leaves.
The American Dagger Moth is found through North America east of the Rocky Mountains. This species prefers deciduous forests but can sometimes live in urban areas with large stands of deciduous trees. The caterpillars feed upon the leaves of oak, alder, elm, willow and many other tree species, especially favoring birch and maple leaves. Adult American Dagger Moths are the largest moths within their home range. They are not considered endangered.