Marble Hill is a neighborhood in Boston.
The Harlem River is an 8 mi tidal strait flowing between the Hudson River and the East River and separating the island of Manhattan from the Bronx on the New York mainland . Manhattan ( [ mænˈhætən ] , [ mənˈhætən ] ) is the most densely populated borough of New York City , its economic and administrative center , and the city 's historical birthplace . Marble Hill, Manhattan . It is the only Manhattan neighborhood on the mainland of North America . The Bronx ( [ ˈbrɒŋks ] ) is the northernmost of the five boroughs of New York City , within the U.S. state of New York .