Youghiogheny River Lake now has two forests registered into the Old-Growth Forest Network, which is a nationwide nonprofit with volunteers across the country who find the last remnants of old-growth forests in North America. The two newly-discovered forests are Klondike Ridge forest in Pennsylvania and the Mill Run forest in Maryland.
Less than one percent of all forests east of the Mississippi River are considered old growth, containing trees older than 70 or 80 years old.