Dundalk Bay (Irish: Cuan Dhún Dealgan) is a large (33 km2), exposed estuary on the east coast of Ireland.

The inner bay is shallow, sandy and intertidal, though it slopes into a deeper area 2 km from the transitional water boundary.

[2] It is predominantly influenced by the sea, though several rivers drain into the bay from the west.

The area of sand, gravel and mud exposed at low tide amounts to over 4,000 ha (10,000 acres).

These are rich in polychaete worms, bivalve molluscs and crustaceans which are the main food for the tens of thousands of waders, gulls and waterfowl that feed here.