Bethesda Softworks (The Elder Scrolls V: Skyrim, Fallout 3) hasn’t released any details regarding the next Fallout game as of yet, but there’s a rumor circulating around the Internet that the next game’s setting will be Boston. This rumor apparently originated out of MIT (the Massachusetts Institute of Technology) in Boston, where Bethesda is said to currently be doing research.
MIT and Bethesda actually do have a close connection as MIT is a part of the Fallout Universe, known as “The Institute” within the world of the games. Massachusetts is also a part of the Fallout Universe, called “The Commonwealth”.
All of this is based on word of mouth so fans of the series probably shouldn’t get their hopes up just yet. However, Bethesda has said that another Fallout game is on the way.