The Commonwealth is the area in and around the pre-War city of Boston. It is most popular for The Institute at its center. While never a peaceful place since the war, being considered almost as bad as the Capital Wasteland was in the past, the Commonwealth is now filled with conflict as the Institute has engaged in a civil war.


After the Great War occurred in 2077, the surviving members of the Massachusetts Institute of Technology met in their mostly intact facilities. Agreeing that the War was caused because imbeciles were allowed to run the world's governments, the heads of MIT founded "The Institute", a faction where the intelligent were the leaders. Meanwhile, those with average intelligence, or below, were could only be a part of the Institute as menial workers. With the Institute's heavy focus on research, the need for these workers has recently ended, however, with their newest invention: the android. For this reason, all of the lower class, excluding those related to the upper class, were immediately forced out of the Institute, with their roles replaced by the more efficient androids.

These newly unemployed workers retreated to the southern half of Boston, soon after founding their own faction, The Union. Since the Union's creation, there has been a great amount of hostility between them and the Institute. In 2299, a squad of androids opened fire on some Union members, sparking a full-scale war between the two. Normally, the Institute could deal with this with ease, but the start of this conflict was followed immediately by another one. The son of Killian, the Institute's Head of Biology, was tested and designated as lower class. Not wanting his son to have such a low status, Killian began a campaign to change the Institute's class system. This has sparked a small-scale civil war within the Institute, with Killian leading the side for change while the Head of Economics, Marcus, leads the side to keep the status quo.


When entering the Commonwealth, the player will start on I-95, either to the north or south depending on where they are coming from. The Commonwealth is divided into two areas, an inner and an outer area. The outer area of the Commonwealth is mostly abandoned ruins filled with raiders and various creatures, including ghouls, deathclaws and shades. Small settlements appear amongst the ruins, namely Newton, Wonderland, Quincy and other places. The inner area consists of Boston to the south, ruled by the Union, and the Institute to the north, with what's left of the river dividing them.

Entering the inner area is usually impossible but with both the Union and Institute distracted, various holes have been left in their defenses. It is possible to convince the still present guards to allow one entry. Getting inside is only half the battle though, since both factions may become hostile towards the player, especially if the player character is an android. The outer area is free to navigate but can be difficult. If one does not have access to the inner area, getting around the outer area will either require going a full circle around the city or navigating the still functioning metro tunnels.

Related quests


  • Despite Killian being the apparent "good" choice to side with during the Institute's civil war, siding with him causes a large number of problems, with less androids and resources available during the final battle of the game, mentions in the endings of the Institute suffering from drought, and various conflict between him and the other faction leaders.
  • Marcus, on the other hand, causes the Institute to expand and prosper in the years to come and gets along with the factions from the surrounding regions, although there is still mentions of some hostility with the Union.