Al`le*ghe"ni*an (?), a. Also Al`le*gha"ni*an. (Biogeography) Pertaining to or designating the humid division of the Transition zone extending across the northern United States from New England to eastern Dakota, and including also most of Pennsylvania and the mountainous region as far south as northern Georgia.

Al`le*ghe"ni*an (?), a. Also Al`le*gha"ni*an. (Biogeography) Pertaining to or designating the humid division of the Transition zone extending across the northern United States from New England to eastern Dakota, and including also most of Pennsylvania and the mountainous region as far south as northern Georgia.