Byberry Hospital at Weird USA - Information and links related to Byberry Mental Hospital.
Exploring and Modern Ruins - Abandoned buildings in Pennsylvania and New York's Hudson Valley.
Haunted Pennsylvania - The galleries of abandoned asylums, resorts and so on will interest local explorers able to overlook the talk of ghosts, orbs and such nonsense.
Hobogan - Pennsylvania urban ruins society
with message boards, photos, and information.
Itsapaisleything - Site focussing on abandoned places, unfortunately featuring many broken links on the moment.
Northstar Gallery - Eastern State Penitentiary - History and stunning photographs of this abandoned penal facility in Philadelphia.
Pennhurst - A collection of everything in any way related to Pennhurst School for the Mentally Retarded. Also, some animated skull clipart.
Pittsburgh Urban Explorers - Trips to abandoned buildings, bridges and secure sites in the area around Pittsburgh (currently down, hopefully temporarily).
Underground Miners Website - Exploring abandoned coal mines in northeastern Pennsylvania.
Story of Byberry - Another site devoted to the abandoned Byberry Mental Hospital.
S*Team Invasion - A hybrid group of urban explorers and parkouristes operating out of Gettysburg.