Shinjuku is one of the 23 city wards of Tokyo, but the name commonly refers to just the large entertainment, business and shopping area around Shinjuku Station.

Shinjuku Station is the world's busiest railway station, handling more than two million passengers every day. It is served by about a dozen railway and subway lines, including the JR Yamanote Line. Shinjuku is also one of Tokyo's major stops for long-distance highway buses. A large bus terminal, named Busta Shinjuku, is conveniently located on top of the railway station.