Poison Oak Geography:

Poison Oak is found everywhere west of the Rocky Mountains besides Alaska and Hawaii. It has also been reported in some southeastern states like Florida and Georgia. It is rarely found above 4,000 feed elevation, but it has been reported up to 5,000 feet.

It is very hardy and adaptable, and can grow in areas with as little as 8 to 10 inches of annual rainfall. Poison oak seems to grow best in moist, slightly shady areas, but can also thrive in open areas with adequate moisture.