The source of the Hudson River is Lake Tear of the Clouds in the Adirondack Park at an altitude of 4,322 feet (1,317 m). However, the river is not cartographically called the Hudson River until miles downstream. The river is named
Feldspar Brook until its confluence with the
Opalescent River, and then is named the Opalescent River until the river reaches
Calamity Brook, flowing south from the outlet of Henderson Lake. From that point on, the stream is cartographically known as the Hudson River. The U.S. Geological Survey (USGS) uses this cartographical definition.
The Hudson River flowing out of Henderson Lake in Tahawus
The longest source of the Hudson River as shown on the most detailed USGS maps is the "Opalescent River" on the west slopes of Little Marcy Mountain, originating two miles north of Lake Tear of the Clouds, several miles, past the Flowed Lands, to the Hudson River. and a mile longer than "Feldspar Brook", which flows out of that lake in the Adirondack Mountains. Popular culture and convention, however, more often cite the photogenic Lake Tear of the Clouds as the source.
Upper Hudson River
Using river names as seen on maps, Indian Pass Brook flows into Henderson Lake, and the outlet from Henderson Lake flows east and meets the southwest flowing Calamity Brook. The confluence of the two rivers is where maps begin to use the Hudson River name. South of the outlet of Sanford Lake, the Opalescent River flows into the Hudson.
The Hudson then flows south, taking in Beaver Brook and the outlet of Lake Harris. After its confluence with the Indian River, the Hudson forms the boundary between Essex and Hamilton counties. In the hamlet of North River, the Hudson flows entirely in Warren County and takes in the Schroon River. Further south, the river forms the boundary between Warren and Saratoga Counties. The river then takes in the Sacandaga River from the Great Sacandaga Lake. Shortly thereafter, the river leaves the Adirondack Park, flows under Interstate 87, and through Glens Falls, just south of Lake George although receiving no streamflow from the lake. It next goes through Hudson Falls. At this point the river forms the boundary between Washington and Saratoga Counties. Here the river has an elevation of 200 feet (61 m). Just south in Fort Edward, the river reaches its confluence with the Champlain Canal, which historically provided boat traffic between New York City and Montreal and the rest of Eastern Canada via the Hudson, Lake Champlain and the Saint Lawrence Seaway. Further south the Hudson takes in water from the Batten Kill River and Fish Creek near Schuylerville. The river then forms the boundary between Saratoga and Rensselaer counties. The river then enters the heart of the Capital District. It takes in water from the Hoosic River, which extends into Massachusetts. Shortly thereafter the river has its confluence with the Mohawk River, the largest tributary of the Hudson River, in Waterford. The river then reaches the Federal Dam in Troy, marking an impoundment of the river. At an elevation of 2 feet (0.61 m), the bottom of the dam marks the beginning of the tidal influence in the Hudson as well as the beginning of the lower Hudson River.
Lower Hudson River
South of the Federal Dam, the Hudson River begins to widen considerably. The river enters the Hudson Valley, flowing along the west bank of Albany and the east bank of Rensselaer. Interstate 90 crosses the Hudson into Albany at this point in the river. The Hudson then leaves the Capital District, forming the boundary between Greene and Columbia Counties. It then meets its confluence with Schodack Creek, widening considerably at this point. After flowing by Hudson, the river forms the boundary between Ulster and Columbia Counties and Ulster and Dutchess Counties, passing Germantown and Kingston. The Delaware and Hudson Canal meets the river at this point. The river then flows by Hyde Park, former residence of Franklin D. Roosevelt, and alongside the city of Poughkeepsie, flowing under the Walkway over the Hudson and the Mid-Hudson Bridge. Afterwards, the Hudson passes Wappingers Falls and takes in Wappinger Creek. The river then forms the boundary between Orange and Dutchess Counties. It flows between Newburgh and Beacon and under the Newburgh Beacon Bridge, taking in the Fishkill Creek. In this area, between Gee's Point at the US Military Academy and Constitution Island, an area known as "World's End" marks the deepest part of the Hudson, at 202 feet (62 m). Shortly thereafter, the river enters the Hudson Highlands between Putnam and Orange Counties, flowing between mountains such as Storm King Mountain, Breakneck Ridge, and Bear Mountain. The river narrows considerably here before flowing under the Bear Mountain Bridge, which connects Westchester and Rockland Counties.
Afterward, leaving the Hudson Highlands, the river enters Haverstraw Bay, the widest point of the river at 3.5 miles (5.6 km) wide. Shortly thereafter, the river forms the Tappan Zee and flows under the Tappan Zee Bridge, which carries the New York State Thruway between Tarrytown and Nyack in Westchester and Rockland Counties respectively. At the state line with New Jersey the west bank of the Hudson enters Bergen County. The Palisades are large, rocky cliffs along the west bank of the river; also known as Bergen Hill at their lower end in Hudson County. Further south the east bank of the river becomes Yonkers and then the Riverdale neighborhood of the Bronx in New York City. South of the confluence of the Hudson and Spuyten Duyvil Creek, the east bank of the river becomes Manhattan. The river is sometimes still called the North River at this point. The George Washington Bridge crosses the river between Fort Lee and the Washington Heights neighborhood of Manhattan. The Lincoln Tunnel and the Holland Tunnel also cross under the river between Manhattan and New Jersey. South of the Battery, the river proper ends, meeting the East River to form Upper New York Bay, also known as New York Harbor. Its outflow continues through the Narrows between Brooklyn and Staten Island, under the Verrazzano Bridge, and into Lower New York Bay and the Atlantic Ocean.