The East River, running alongside every borough of New York City except for Staten Island is not actually a river, but a tidal estuary. The boroughs of New York are connected by seven bridges over the East River: from north to south, the Throgs Neck Bridge, the Bronx-Whitestone Bridge, the Triborough Bridge, the Queensborough Bridge, the Williamsburg Bridge, the Manhattan Bridge, and the Brooklyn Bridge. There are also thirteen tunnels under the East River. Two for vehicular traffic: The Brooklyn-Battery Tunnel and Queens-Midtown Tunnel, one for inter-city and commuter railroad traffic connecting to Penn Station and 10 for subway traffic.
The East River begins at the Long Island sound at the eastern boundary of New York City and flows between the boroughs of Bronx and Queens under the Throgs Neck and Whitestone bridges. At approximately its midpoint, the East River changes from going east-west to going north-south at a turbulent channel called Hell Gate. Hell Gate is spanned by both the Triborough Bridge and the Hell Gate Bridge, the latter being the longest railroad bridge in the world. The southern segment of the river is the more famous one, with Manhattan on the west side and Queens and Brooklyn on the east.
In addition to several minor islands, the East River contains Riker's Island, North and South Brother Islands in the upper segment and Roosevelt Island (formerly Welfare Island) in the lower segment. Ward's Island and Randall's Island are at the junction of the two sections. The latter two have been joined by landfill.