With some exceptions, all first and second-year students will live on-campus, and students are guaranteed on-campus housing throughout their undergrad (also with some asterisks). See https://www.northeastern.edu/housing/university-housing/ for official information, and check out this list of residence halls for info on particular buildings.
Housing Assignment and Selection
Amenities and Programs
University housing places students with Resident Assistants who can help with questions or troubles they may have with housing, navigating college, and they also put on fun events.
Students living on campus are represented by the Resident Student Association, an independent student government body.