Maryland and Pennsylvania Railroad Preservation and Historical Society
- This is a nonprofit organization, whose mission is to collect and preserve the history of the Maryland and Pennsylvania Railroad in personal recollections, photographs, documents, memorabilia and models.
- http://www.maparailroadhist.org/

Society of the Ark and the Dove, The
- Organization for descendants of Lord Baltimore and of those who sailed aboard the Ark and the Dove to settle Maryland
- http://www.thearkandthedove.com/

Maryland Historical Trust
- Assists in identifying, evaluating and preserving the state's significant prehistoric and historic sites, cultural landscapes and artifacts, as well as less tangible human and community traditions. Includes information about registered landmarks, archeolo
- http://www.marylandhistoricaltrust.net/

Edgar Allen Poe Society of Baltimore
- Although Richmond is the place Poe most considered home, Baltimore defines the beginning and the end of his life. Also links to Baltimore's Poe House and Museum and Poe's grave.
- http://www.eapoe.org/

Maryland Historical Society
- Established in 1844 as a private nonprofit institution to collect, preserve, and interpret the objects and artifacts that illuminate the state's history.
- http://www.mdhs.org/

D'addezio.com - Maryland Historical Societies
- Provides address information and links to historical societies in each county within the state of Maryland.
- http://www.daddezio.com/society/hill/SH-MD-NDX.html