From its origin high in the Adirondack Mountains to the bustling New York–New Jersey Harbor, the Hudson River watershed is a rich and magnificent ecosystem.
Unlike most rivers, the Hudson is a tidal estuary, meaning its waters are a mix of fresh mountain runoff and salty ocean water. Twice a day, the tides push saltwater as far north as Poughkeepsie, 70 miles from New York City. These tides create a brackish blend of saltwater and freshwater, an environment that supports an astonishing variety of life. Even at the Federal Dam in Troy, 153 miles from the Atlantic, the river feels the pull of the tides.
Where the Hudson River begins and ends
Stretching 315 miles, the Hudson begins its journey at Lake Tear of the Clouds on Mount Marcy, New York’s tallest peak. From these pristine headwaters in the Adirondacks, the river winds through valleys, forests, and towns, fed by tributaries, streams, creeks, and rainfall until it reaches New York Harbor and empties into the Atlantic Ocean.
Photo: Erica Capuana, NYS DEC, Division of Fish and Wildlife
What lives in the Hudson River watershed
The Hudson teems with life, supporting 184 identified species of native fish. Some of its most iconic residents include the American eel, American shad, river herring, Atlantic sturgeon, and shortnose sturgeon. These species are uniquely adapted to move between saltwater and freshwater (“diadromous”). Some migrate upriver to spawn in freshwater before returning to the Atlantic Ocean (“anadromous”), whereas others live in freshwater and spawn in the ocean (“catadromous”). Eels spawn far from New York in the Sargasso Sea near Bermuda, then travel all the way to tributaries of the Hudson River to grow and mature.
This extraordinary migration is guided by fishes’ circadian rhythms as well as changes in temperature and the length of the day, which trigger their relentless drive to spawn. Many of these migratory species leave their fertilized eggs behind in freshwater, ensuring that their offspring have the best chance of survival. After spawning, the adult fish return to the ocean to recover and forage. Among them, the
endangered Atlantic sturgeon, a species that has been on earth for at least 120 million years, stands out as one of the river’s ancient inhabitants.
In addition to fishes, the Hudson supports birds, amphibians, mammals, and insects that rely on the river’s banks and waters. Eagles soar above, turtles sunbathe on the shore, and beavers build their homes in the small tributaries that feed into the Hudson.
What kinds of habitats are in the Hudson
The river's diverse habitats range from tidal marshes and wetlands to rocky shoals, creating ideal environments for a diverse range of species. The lower estuary's tidal marshes serve as nurseries for young fish, while the waters of the upper Hudson sustain thriving freshwater ecosystems.
Plant life along the Hudson is as varied as its wildlife. Near the brackish waters of the lower river, salt marsh grasses thrive. Farther upriver, freshwater plants like sedges, cattails, and water lilies flourish, providing essential habitat for a variety of aquatic and terrestrial species, and naturally filtering the river's waters.
How you are connected to the Hudson
The Hudson River watershed is critical to environmental health, including human health. From the Adirondack headwaters to the estuary’s mouth – across cities, forests, and wetlands – the Hudson nourishes and supports all the life in our vast region. From drinking water supplies to fish that are safe to eat, we rely on the water for our safety and sustenance.
What you can do to help the river
At Riverkeeper, we are committed to restoring the abundance of migratory fish and protecting the entire ecosystem. You can help by signing up for our newsletter at the bottom of this page and
supporting efforts like the
removal of obsolete dams, restoring miles of critical spawning habitat for iconic Hudson River fish species.
Together, we can celebrate and ensure the longevity of this vital natural resource for generations to come.
