Where Does the Delaware River Start?

Written by Becky Mathews
Updated: August 5, 2022
Image Credit ESB Professional/Shutterstock.com
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The Delaware River is a large, free-flowing freshwater river that touches five states. It’s known for its varied wildlife and provides excellent quality water to over 13 million people.

A lifeline for people and wildlife for millennia, the Delaware River is not the longest in the United States, but it’s steeped in history and interesting facts.

Let’s take a look at this ancient river, starting with this simple but not-so-simple question, where does the Delaware River start?

Where Does the Delaware River Start?

Delaware River with Philadelphia Skyline
The Delaware River starts in the Catskill Mountains of New York.

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The Delaware River starts in the Catskill Mountains of New York. It springs from two branches. The Western branch begins near Mount Jefferson, and the Eastern Branch at Grand Gorge near Roxbury.

It’s not unusual for rivers to start at different sites before joining to create a vast body of water. For example, The Mississippi River starts in Lake Itasca, but Lake Itasca is fed by numerous streams. Sometimes it’s very hard to pinpoint an exact spot!

Delaware River springs from Mount Jefferson and Grand Gorge before merging in Hancock, New York, and traveling down to the Delaware Bay.

What States Does the Delaware River Flow Through?

Upper Delaware Scenic And Recreational River
The Delaware River runs through Delaware, New York, New Jersey, Maryland, and Pennsylvania.

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The Delaware River flows through Delaware, New Jersey, New York, Maryland, and Pennsylvania.

Each state makes use of the river water for drinking and leisure. Every day 4 billion gallons of water are drawn from the Delaware River Basin. It’s a major part of the states it flows through.

Where Does the Delaware River End?

The Delaware River ends in Delaware Bay between Delaware and New Jersey, on the Eastern coast of the United States. The bay is an estuary that covers 2,030 square kilometers.

River Delaware’s fresh water mingles with the salty Atlantic Ocean. The mix creates salt marshes and mudflats that attract really interesting wildlife. An article in the Journal of Biological Conservation shows that its mixture of habitat types, ranging from mudflats to high marshes, sustained high populations of shorebirds.

As well as a haven for wildlife, the bay is an important tourist destination for hunting, fishing, and boating. It’s critical to navigation, forming part of the Atlantic Intracoastal Waterway and reaching Philadelphia City via a 180-meter-wide channel.

How Long is the Delaware River?

The Delaware River is 330 miles long, and all of it is an interstate boundary. It’s not the longest river by a long shot, but it outstretches the Hudson River, which only manages 315 miles.

It isn’t easy to pinpoint an exact width because the Delaware River winds its way down to the coast. It meanders, so its width alters as it goes. It’s too wide to cross without a boat or bridge, though!

How Old is the Delaware River?

Delaware Water Gap National Recreation Area
The Delaware River is very old and has an interesting history.

ESB Professional/Shutterstock.com

Melting icecaps from the Ice Ages created the Delaware River during the Pleistocene Epoch. This epoch was anything from 2 million to 20,000 years ago.

The Delaware River is very old indeed, and it has some interesting history. It was discovered by Henry Hudson in 1609 but got its name from Thomas West, 3rd Baron De La Warr. He lived from 1577-1618 and was the Virginia colony’s first governor.

The Delaware River was a key crossing point during the American revolution. George Washington crossed it on Christmas Day in 1776, leading across troops from Bucks County, Pennsylvania.

But before any Europeans put their mark on it, the Delaware River was called Lenape Wihittuck and was home to the Native American Lenape tribes.

How Deep is the Delaware River?

The Delaware River has many different depths, but its deepest point is 113 feet at Big Eddy in Narrowsburg, New York.

Most of its shoreline is around 4-6 feet, but the center is 30-40 feet. It’s very easy for swimmers to get out of their depth.

The river is artificially deepened for cargo ships in some areas. There’s a 103-mile stretch from Camden and Philadelphia to Delaware Bay that’s been deepened from 40 feet to 45 feet. That project wrapped up in 2018 and allowed large cargo ships to move about easily.  

What Animal Live in the Delaware River?

Bald Eagle flying over a lake.
Overwintering bald eagles live on the Delaware River.

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Birds, fish, and mammals live in, on, and near the Delaware River. It’s an incredible habitat for wildlife with over 400 types of birds and 90 different fish species.

The Upper Delaware River Basin attracts overwintering inland bald eagles. Experts have counted up to 40 there in one year alone. Twenty-seven species of migrating warblers have been identified there during spring and fall migrations, with many Species of Concern present.

As for fish, it’s home to endangered American eels. That’s because they’re the only catadromous fish in North America. This means they spawn in saltwater but live in freshwater. The freshwater Delaware River is perfect for them because it ends in the salty Atlantic Ocean.

Shad are another type of fish that utilize the Delaware River, migrating in spring to spawn in the freshwater. Shad travels over 12,000 miles during their life. They are very hardworking fish.

River otters are plentiful too. They nest on the banks and hunt fish or mollusks in the river. Most sightings are near the nature reserves, where they find safety from hikers and hunters.

What is the Longest River in the United States?

The longest river in the United States is the Missouri River.

iStock.com/Matthew Howieson

The longest river in the United States is the Missouri River. The Missouri River is 3,768 kilometers long, so much longer than the Delaware River! It’s so long that it drains 1/6th of North America’s land.

The Missouri River starts in the Rocky Mountains and is actually a tributary of the Mississippi River. The Mississippi River is the second-longest river in the United States at 3,544 kilometers. It’s not a great deal shorter than the Missouri River, and it’s just as important to humans and wildlife.

So, we’ve learned that the Delaware River starts in the Catskill Mountains in New York. It flows from two points. The Western branch starts near Mount Jefferson, and the Eastern Branch at Grand Gorge near Roxbury.

Along its course, the Delaware River merges into one river that supports human and animal life before ending in the Atlantic Ocean at Delaware Bay.

It might not hit the top ten longest rivers in the United States, but it’s an incredible river with a rich history that supports modern-day life.

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