East River and Williamsburg Bridge, from Brooklyn Bridge

Title: East River and Williamsburg Bridge, from Brooklyn Tower of Brooklyn Bridge, New York City. Publisher: H.C. White Co. North Bennington, Vt. Copyright claim 1907. Print on card mount (9 x 18 cm, stereograph format). Source: Library of Congress Prints and Photographs Division Washington, D.C.

Despite its name, the East River is actually a saltwater tidal estuary. It connects New York Harbor on its south end to Long Island Sound on its north end. It divides Manhattan Island from Queens and Brooklyn, also on Long Island. It also separates the borough of Queens on Long Island from the Bronx on the North American mainland.