Eastern Commonwealth

The Eastern Commonwealth was one of the thirteen commonwealths of the pre-War United States. Created in the early 21st century, it was comprised of the former states of West Virginia, Delaware, Pennsylvania, New Jersey and New York.

Great Lanta
Great Lanta is an area mentioned by Father Clifford, and is the post-War remains of Atlantic City. It was invaded by slavers at one point. However, one slave group led by a man named Ehren was disbanded by Ehren himself with the help of Saint Monica, and the slaves were freed.

The Pitt
The post-War ruins of Pittsburgh are the basis of the Fallout 3 add-on The Pitt. Ruled by slavers, it is plagued by trogs, humans who degenerated due to the hazards produced by the city's three irradiated rivers over the decades.

Philly
Philly, once reminisced by Abraham Washington, was the post-War ruins of the city of Philadelphia. He sent an expedition there to recover the Liberty Bell, to bring back and display at the Capitol Preservation Society.

Monroeville
A town mentioned by Everett. The Pitt raiders go out on raids in the town, and is overrun by trogs.

New York

 * Albany (Mentioned in Point Lookout)
 * New York City (Mentioned in the Fallout Bible 0, Fallout 3, and Dead Money)
 * Flatbush (Mentioned in Mothership Zeta)
 * Niagara Falls (Mentioned in Point Lookout)

New Jersey

 * Great Lanta (Mentioned in Fallout 3)

Pennsylvania

 * Monroeville (Mentioned in The Pitt)
 * Philadelphia (Mentioned in Fallout 3)
 * The Pitt (Appears in The Pitt, mentioned in Fallout 3 and Point Lookout)

Appearances
The Eastern Commonwealth appears in the Fallout 3 add-on The Pitt, and is also mentioned in Fallout 3 and its add-ons Point Lookout and Mothership Zeta. It is also mentioned in the Fallout: New Vegas add-on Dead Money, Fallout 4 (as well as a cameo appearance of the Statue of Liberty in the Atomic Command game), and the Fallout Bible.