1. The Hudson is a Tidal Estuary

Twice a day the waters of the Atlantic rise higher than the levels of the Hudson. At high tide, salt water pushes up the Hudson, raising the water levels. When the tide goes back out, the Hudson switches back to its normal flow direction back out to sea.

The salinity levels vary by location and time of year. In the spring, the fresh water line is around Yonkers. At the end of summer, the river is salty all the way up to Newburgh.

2. The Hudson has lots of blue crab

Maryland isn’t the only place that has blue crab. Commercial and recreational fisheries up and down the Hudson catch blue crab from June through October.

They migrate up the river in the summer to feed as the salt line moves further north, then they migrate back into saltier waters by the bay in the winter.

I regularly see blue crab around marshes at low tide in Yonkers in the summer.

3. Tappan Zee Bridge is at the river’s second widest point in order to keep toll revenue going to New York State

The Tappan Zee Bridge, which goes from Rockland County to Westchester County near Tarrytown, is at the Hudson’s second-widest point, even though the river gets much narrower closer to NYC.

The reason that the location neat Tarrytown was chosen was because it is just outside of Port Authority’s 25 mile jurisdiction. That means toll revenue would go to New York State, not Port Authority.

4. The Union used The Palisades for Target Practice during the Civil War

When the Union Navy build the ironclad USS Passaic, they needed a safe place to test its cannons. They picked the New Jersey Palisades. On November 15, 1862, the crew sailed the ironclad up the Hudson and pointed its cannons at the rock cliffs. As James M. Madden writesArchived Link,

It misfired several times, to the amuse- ment of those officers aboard who had predicted that the ship’s turret design would interfere with effective gunnery. And then, on the fourth attempt, the Dahlgren fired. That first round splintered the rock wall and produced a massive echo that witnesses likened to the explosion of a powder mill. Despite the noise, the navy was satisfied, as there was no concussion or smoke inside the ship’s gun turret, despite dire predictions from critics. Three more shots produced as many more echoes and showers of shattered rock. An Irishman aboard, awed by the destructive demonstration, declared the Passaic a “floating divil.”

5. Oysters are coming back

Oyster beds once stretched from the mouth of the Hudson all the way up to Tarrytown. Due to pollution and overfishing, they’ve been almost absent for the last few decades.

Good news: The river is cleaner now than it has been in decades and at super low tides, you can see evidence of oyster beds making a comeback.