Before the war, the Faneuil Hall branch of the Fallon's department store chain was victim to thousands of dollars worth of merchandise lost due to lack of security in the Faneuil Hall marketplace. Several merchants threatened to sue for breach of contract over the security issues, and Fallon's prepared to withdraw outright. With the pressure building, the mayor insisted that the Protectrons be installed to ensure the thefts would stop.
The following week, a massacre occurred at the building. The Protectrons that were installed killed seven people, including five alleged shoplifters, one bystander, and one Fallon's cashier. A public relations nightmare followed, and sales dropped 81%.
After the war, the interior of Faneuil Hall is inhabited by super mutants, who roam the building alongside their mutant hounds. Other Fallon's locations in the region include the flagship West Roxbury station Fallon's department store, Fallon's Basement in the Diamond City market, a building in the General Atomics Galleria, a location in Concord, and a branch near Monsignor Plaza.
Fallon's (Faneuil Hall) only appears in Fallout 4.