Nittany Grotto
- Chapter of the National Speleological Society meets at Penn State University. Includes contact information, calendar of events, publications and photo gallery.
- http://www.clubs.psu.edu/up/nittanygrotto/

York Grotto
- Chapter of the National Speleological Society. Advocates scientific study of caves, surveying, conservation and historical studies. Includes meeting and membership information, upcoming events and contacts.
- http://www.yorkgrotto.org/

The Bucks County Grotto
- Dedicated to discovery, exploration, conservation, preservation and historical research in Southeastern Pennsylvania. Includes membership requirements and contact information.
- http://www.caves.org/grotto/bcg/

Pennsylvania Cave Conservancy
- Affiliate of the National Speleological Society. Mission is to protect cave resources within the Mid-Appalachian Region (Pennsylvania, Maryland, New Jersey and Delaware). Open to member grottos in the MAR. Includes contacts and calendar.
- http://www.caves.org/conservancy/pcc/Home.shtml

Franklin County Grotto
- Chapter of the NSS since 1981 and based in New Franklin. Dedicated to exploration and conservation. Includes meeting and membership information, trip reports and contacts.
- http://crossroads.ws/fcg/

Philadelphia Grotto
- Chartered 1947 for cave conservation, exploration, education and research. Includes calendar of events, contacts, meeting and membership information, and articles about safety and geology.
- http://www.phillygrotto.org/

Pittsburgh Grotto
- Chapter of the NSS. Dedicated to exploration, documentation and conservation. Features calendar of events, meeting and contact information, membership form and trip reports.
- http://www.karst.org/pgrotto

Mid-Atlantic Karst Conservancy
- Established in 1997 to preserve, acquire and manage karst areas. Includes details of current projects and contact information.
- http://www.karst.org

Loyalhanna Grotto
- Chapter of NSS since 1987. Located in Indiana, Pennsylvania and meets monthly in Apollo. Includes safety tips, equipment checklist, membership application and contacts.
- http://www.karst.org/loyalhanna/

Bald Eagle Grotto
- Located in Central Pennsylvania. Founded in 1986 for exploration and conservation. Conducts cave rescue training sessions. Includes contact information.
- http://www.kbsb.com/beg/