Dundalk Bay 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. It is predominantly influenced by the sea, though several rivers drain into the bay from the west. In the northwest corner of the bay, the Castletown River cuts through the intertidal zone and the smaller River Fane flows into the southeast corner. While the bay is largely made up of intertidal flats, there is a significant area of salt marsh on the western shore. The catchment around the bay is of mixed agriculture and urban land use. The Castletown River is routinely dredged for navigation purposes for the deep water port of Dundalk.