A survey was carried out and it was decided that walls would be built on both sides (north and south) of Dublin Harbour.
North Bull Wall was completed in 1821. Longshore drift now deposited material behind the North Bull Wall. This helped to build a large sand spit, which developed into North Bull Island.
The island reached its current length in 1902. It is approximately 5 km long and 1 km wide at its widest point.
Managing information and thinking
Locate both the North and South Bull Walls on this OS map. 39