The rock formation is about 300-million years old. The walking path leads into the heart of the rock formations. There is one large area called "Devil's Dining Room." There's a long tight crevice from this room leads to the "Devil's Dungeon" and the "Devil's Kitchen." A tight passage near the end of the path leads to a room called "Ice Cave" since in winter this spot keeps water frozen longer than any other places around it. One of the newest features is "Rock House." Roland Welker won the History Channel's Season 7 television show, "Alone" by surviving 100 days in Canada's arctic wilderness. "Rock House" is a replica of the shelter he built to live in for those 100 days.
If you go:
The park is free. The path is rugged so be sure to wear good hiking shoes and do not go on a rainy day. There is a park and primitive camping is allowed.
Links:

1921 Bilgers Rocks Rd
Grampian, Pennsylvania 16838 USA
nfobilgersrocks@gmail.com
Phone Numbers:
park
+1 (814) 236-3597
+1 (814) 236-3597