Within Rothrock State Forest in Huntingdon County, a 463-acre area in Detweiler Hollow is recognized for the virgin white pine and hemlock that grow there. The giant old-growth trees shade an understory of massive rhododendron that covers both sides of the Detweiler branch of Standing Stone Creek. Additional tree species in the area include red, scarlet and chestnut oaks and red maple. The area is situated on the northern outer slopes of Grass Mountain. The ridge is composed of very steep, talus-strewn slopes and a small area of open talus fields. The Mid-State Trail follows the stream that runs for approximately one mile through the center of the natural area.
Directions
East of State College on US Rt 322, turn south on Bear Meadows Road at the sign for Tussey Mountain Ski Resort. Detweiler Run Natural Area is 5 miles south along this road, just north of the Alan Seeger Natural Area.