Haulbowline Island was first fortified in 1602 but it was during the Napoleonic Wars that significant changes were made. The Island was handed over to the Royal Navy in 1806 and this resulted in the building of:
- An Ordnance Yard was built on the western side of the island
- A Martello Tower to protect the Ordnance Yard
- Two Magazines on on Rocky Island for 25,000 barrels of powder
- A victualling yard
In the 1860s the Island underwent major development with the building of a Royal Navy Dockyard that doubled the size of the island. The Dockyard had a coal store and dry dock.
Fortifications were built to protect the Naval Base as shown on the plan.
The site is now used by the Irish Navy.