The Delaware Estuary

The State of Delaware includes a portion of three major estuaries, or tidal watersheds, where freshwater rivers drain from the land into the Atlantic Ocean. These include the Delaware Estuary, the Chesapeake Bay, and a collection of estuaries referred to as the Inland Bays. Of these, the Delaware Estuary claims the largest portion of the First State, though its watershed actually extends far into New Jersey and Pennsylvania as well.

The Delaware Estuary is a vital ecosystem that is not only home to the largest population of spawning horseshoe crabs in the world, but also the second-largest concentration of migrating shorebirds anywhere in the Western Hemisphere. Meanwhile, its waters serve as an important fishery for fish, shellfish and crabs. And that's just the tip of the iceberg. The estuary is also home to millions of people, the largest freshwater port in the world, and five of the largest oil refineries on the entire East Coast — making it an economic powerhouse as well as a natural treasure. Protecting its environment is of the utmost importance to many species, not the least of which is humans.

There is much to see and do here in the Delaware Estuary, and is but a small testament to that. We hope you will visit Delaware, experience the estuary and the wildlife that call it home, and come away with a better appreciation for its value to the nation. And maybe, just maybe, your outdoor experience will also prompt you to give back to your own watershed, wherever that may be.

To learn more about the Delaware Estuary and the work underway to protect and enhance it for current and future generations, please visit, the online home of the Partnership for the Delaware Estuary, a National Estuary Program.

Photo by Lew & Liz Dumont

Photo by Delaware State Parks