St. George's Harbour is a natural harbour in the north of Bermuda. It serves as the port for the town of St. George's, located on St. George's Island, to its north. To its south is St. David's Island. The harbour and both islands lie within St. George's Parish. It was for two centuries the primary harbour of the British Overseas Territory. Topography The harbour separates St. George's Island in the north and west from St. David's Island in the south and east. Several other islands lie to the south and east, closing the harbour from the open sea to the east, and separating it from Smith's Sound, to the South. It is open to the Atlantic Ocean at Gunner Bay in the northeast, where its mouth is guarded by numerous islands, notably Smith's and Paget Islands. The waters of Bermuda are also protected by coral reef, which can be perilous to sailors. Several other islands lie within the harbour, notably the historically important Ordnance Island. In the south, a long channel, Ferry Reach, links the harbour with another opening to the Atlantic Ocean and the picturesque Castle Harbour. History The original channel used by shipping to access the harbour lies to the south of Paget Island. This was replaced a century ago by dredging out the passage to the north of Paget Island. At the time, the dredging of that passage had been necessary for St. George's to remain a viable port as steam replaced sail (permission for the dredging had to be granted by the Secretary of State for Defence as it would have enabled easier landing of an invading force. approval for this project, and for American investment into the Princess Hotel, was withheld 'til the Parliament of Bermuda agreed to raise a part-time reserve for the British army units in Bermuda). Most freight, today, is offloaded at Hamilton, but St. George's is still used for offloading of gravel and other consignments, by cruise ships visiting the Old Town, and it is the only port of entry for yachts, which must clear H.M. Customs and Bermuda Immigration at Ordnance Island before visiting other parts of the archipelago. To enter St. George's Harbour, sailors must fly a yellow quarantine flag, and navigate the ship towards the Customs dock. Boaters who don't bring their vessel through customs will be fined. Before passing through Bermuda customs, visitors must declare all medicines,