Delaware Bay

Delaware Bay borders New Jersey to the north and Delaware to the south, where the Delaware River meets the Atlantic Ocean. The bay is a major estuary on the Northeast coast of the United States and has historically served as an important maritime channel.

Delaware Bay is recognized as a crucial stopover site for millions of migratory shorebirds, particularly the red knot, which times its annual migration to coincide with the spawning of horseshoe crabs. The birds rely on horseshoe crab eggs as a vital food source to fuel their journey to Arctic breeding grounds.

Each spring, vast numbers of horseshoe crabs come ashore on Delaware Bay beaches to spawn, laying millions of eggs in the sand. This phenomenon is one of the largest horseshoe crab spawning events in the world and directly supports the survival of migratory shorebirds like the red knot.

Delaware Bay is approximately 13 miles wide at its widest point and extends roughly 52 miles from the mouth of the Delaware River to the open Atlantic Ocean. Its broad, shallow waters distinguish it from deeper coastal inlets along the Atlantic seaboard.