Hudson River > Basics


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The Hudson River is not your typical river. In fact, most of the Hudson is actually a tidal estuary where salt water from the ocean combines with freshwater from northern tributaries. This “brackish”, or mixing, water extends from the mouth of the Hudson in NY Harbor to the Federal Dam in Troy, approximately 153 miles.

The salt front of the estuary, where the freshwater runoff meets the saline water, can range from the Tappan Zee Bay near Tarrytown/Nyack in the spring to Newburgh Bay in Poughkeepsie/Newburgh in the late summer or during droughts.

Because the Hudson River is a tidal estuary, meaning it ebbs and flows with the ocean tide, it supports a biologically rich environment, making it an important ecosystem for various species of aquatic life. For many key species, it provides critical habitats and essential spawning and breeding grounds.

To learn more about the unique regions of the Hudson River take A Hudson River Journey.

Traveling Exhibit

A Hudson River Journey is a traveling exhibit produced by Riverkeeper in honor of the 400th anniversary of Henry Hudson's voyage to our shores.

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Riverkeeper’s Mission -is to defend the Hudson River and its tributaries and protect the drinking water supply of nine million New York City and Hudson Valley residents.

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