Prior to 1948, most public transportation in New Jersey was provided by the Public Service Corporation of New Jersey, a utility company that also operated the Public Service Railway division. In 1948, the Public Service Corporation was divided into two entities: the Public Service Electric and Gas Company, which inherited the utility operations, and the Public Service Coordinated Transportation Company (PSCT), which inherited the transit operations. PSCT provided service throughout New Jersey, originally using trolleys and then transitioning to trolley buses, and buses. During the 1970s, the New Jersey Department of Transportation began subsidizing the routes of Public Service, now renamed Transport of New Jersey (TNJ), contracting with TNJ and other companies to operate local bus service throughout New Jersey.
NJ Transit came into being as the result of the New Jersey Public Transportation Act of 1979 to "acquire, operate, and contract for transportation services in the public interest". NJ Transit Bus Operations came into being the following year, when it acquired Transport of New Jersey from PSE&G. Other purchases and buyouts in the 1980s expanded the bus division of NJ Transit, including the acquisition of the Atlantic City Transportation Company in 1987. In 1992 NJ Transit Mercer, Inc., which was the successor to the former "Mercer Metro" operation in the Trenton and Princeton areas, was folded into NJ Transit Bus Operations. In 2010, Morris County operations were taken over under the subsidiary NJ Transit Morris, Inc.
Routes are numbered by where they operate in the state of New Jersey, however, there are a few exceptions to the general rule due to recent changes to some routes operating in Central and North Jersey. Fare and route can also be further elucidated on some of the individual route schedules or the trip planner.