Portland Bill

At its highest point, the island is 150 meters above sea level.

The island is connected to the mainland by a narrow and steeply sided arc of shingle, about thirty kilometers long, called the Chesil Bank.

An idea of how dangerous a navigational hazard the Chesil Bank was cane be gained from the fact that the region where the bank joins the Isle of Portland was called Deadman's Bay.

Even so, the Chesil Bank allowed vessels to ride protected from rough seas and winds to the east of the Bank, in an area of sea called the Portland Road.

The sea off the Bill is one of the most dangerous parts of the English Channel.

A dangerous tidal current called the Portland Race runs between Portland Bill and a large sandbank to the south east of the Bill called the Shambles.

Like Dead-Man's Bay, the name of this sandbank reflects how dangerous a place it was (shambles was the name commonly used from the mid-sixteenth century for places where animals were butchered).
Privately owned lighthouses were built on Portland Bill after the granting of a Royal Patent in 1716, but it was always poorly maintained. The Bill was not reliably lit until the late 1780s, when the lighthouses were equipped with a newly invented array of oil lamps and large polished reflectors.