Delaware River je řeka na východní straně USA, ústící do vod Atlantského oceánu. Řeku objevil Adriaen Block coby část kolonie New Netherlands. Byla pojmenována South River, protože označovala nejjižnější část kolonie.
The river meets tide-water at Trenton, New Jersey. Its total length, from the head of the longest branch to the capes, is 410 miles (660 km), and above the head of the bay its length is 360 miles (579 km). The mean freshwater discharge of the Delaware River into the estuary is 11,550 cubic feet (330 m³) per second.
The Delaware River constitutes in part the boundary between Pennsylvania and New York, the entire boundary between New Jersey and Pennsylvania, and most of the boundary between Delaware and New Jersey. A historical oddity, the Delaware-New Jersey Border is actually at the eastern-most river shoreline within the Twelve-Mile Circle of New Castle, rather than the usual mid river or mid channel borders, causing small portions of the New Jersey peninsula falling west of the shoreline to fall under the jurisdiction of Delaware. The rest of the borders follow a mid-channel approach.
Commerce was once important on the upper river, primarily prior to railway competition (1857).
- The Delaware Division of the Pennsylvania Canal, running parallel with the river from Easton to Bristol, opened in 1830.
- The Delaware and Raritan Canal, which runs along the New Jersey side of the Delaware River from Milford to Trenton, unites the waters of the Delaware and Raritan rivers as it empties the waters of the Delaware River via the canal outlet in New Brunswick. This canal water conduit is still used as a water supply source by the State of New Jersey.
- The Morris Canal (now abandoned and almost completely filled in) and the Delaware and Hudson Canal connected the Delaware and Hudson rivers.
- The Chesapeake and Delaware Canal joins the waters of the Delaware with those of the Chesapeake Bay.
The mean tides below Philadelphia are about 6 feet (2 m). The magnitude of the commerce of Philadelphia has made the improvements of the river below that port of great importance. Small improvements were attempted by Pennsylvania as early as 1771.
In the "project of 1885" the United States government undertook systematically the formation of a 26 ft (8 m) channel 600 ft (180 m) wide from Philadelphia to deep water in Delaware Bay. The River and Harbor Act of 1899 provided for a 30 foot (9 m) channel 600 feet (180 m) wide from Philadelphia to the deep water of the bay.
