The lovely Blue Ridge Mountains extend from southern Pennsylvania to northern Georgia and contain the highest peak east of the Mississippi, 6,684-foot Mount Mitchell, which rises from the Pisgah National Forest, 20 miles north of Asheville, North Carolina. Part of the larger Appalachian range, they owe their poetic name to isoprene, a volatile organic compound released by certain species of trees, which is responsible for their characteristic bluish haze.