Where is poison ivy most commonly foundly?

Altitudes below 4,900 feet (1,500 meters) are the places where poison ivy grows in the United States of America. The perennial is neither poisonous -- although its urushiol provokes allergic reactions in people, not wildlife -- nor an ivy. As a shrub, understory plant, or vine, the plant may be found classified as Toxicodendron orientale in east Asia, Toxicodendron radicans in North America (central and east Canada, mountainous northern Mexico, the United States east of the Rockies), and Toxicodendron rydbergii in central and western Canada and the United States (central, New England, west).