Question: where does the east river start and end
Answer: East River Tidal strait East River and the headquarters of the United Nations in Manhattan as seen from Roosevelt Island ( December 2006 ) Country United States State New York Municipality New York City Tributaries - left Newtown Creek , Flushing River - right Westchester Creek , Bronx River , Bronx Kill , Harlem River Source Long Island Sound - coordinates 40 ° 48 ′ 01 '' N 73 ° 47 ′ 31 '' W ﻿ / ﻿ 40.