| || This page is about the location of Fallout 4. For the 13 pre-War U.S. commonwealths, see United States.|
For European organization of states, see European Commonwealth.
The Commonwealth itself is nothing but a war-ravaged quagmire of violence and despair. Inside the sealed environment of the Institute, however... but the Institute's affairs are none of your concern. Your undeveloped mind couldn't even begin to comprehend what we've accomplished.”— Dr. Zimmer
The Commonwealth is what is left of the pre-War American state of Massachusetts in New England. While traditionally called a commonwealth in itself, before the Great War, Massachusetts was also part of the New England Commonwealth of the United States in the alternate history of the Fallout universe. Most of it is a "war-ravaged quagmire of violence and despair" like much of the rest of the former United States, but it is also where Boston and the mysterious Institute are located.
Little is known about the Institute other than that the scientists working in the sealed environment possess highly advanced technology and technological skills. It has created true artificial intelligence (A.I.) and is capable of manufacturing androids, also referred to as "synths" - short for "synthetic humans". One of its branch, the Synth Retention Bureau, is tasked with recovering renegade synths that escape the Institute and reprogram them. The SRB is mostly composed of Institute coursers who acts as an intervention force.
Another organization active within the Commonwealth, the Railroad, functions in direct opposition to the Institute. Named in honor of the Underground Railroad, the Railroad's mission is the rescue and salvation of synthetic humanoids primarily, though enslavement as a whole is also fought against.
There are more factions in play than The Institute and the Railroad, however. Preston Garvey leads a group called the Minutemen, presently fighting against the vicious bands of raiders which plague the area. The Sole Survivor may find Garvey and his men in Concord after taking heavy losses in a raider skirmish.
The Brotherhood of Steel is present in the vicinity of Boston as well, and own an armored airship named The Prydwen that lurks the skies of Boston. Led by Elder Arthur Maxson, the brotherhood has reverted to its old ways and is now trying to bring the Institute down along with its synths.
- Harkness, Dr. Zimmer and Armitage are from the Commonwealth.
- During the events of Broken Steel, Dr. Li leaves the Capital Wasteland on a trip to the Commonwealth, apparently to clear her head after the final activation of Project Purity. At an unspecified point, she joins The Institute.
- Tobar, captain of the Duchess Gambit, made frequent trips to the Commonwealth when his ferry was in better condition.
- Ishmael Ashur, ruler of The Pitt, mentions The Commonwealth, stating that it has reason to envy the Pitt.
- Marcella mentions the Commonwealth on her terminal in Point Lookout.