Map - Sombrero, Anguilla (Sombrero)

Sombrero, also known as Hat Island, is part of the British Overseas Territory of Anguilla and is the northernmost island of the Lesser Antilles. It lies 54 km north-west of Anguilla across the Dog and Prickly Pear Passage. The distance to Dog Island, the next nearest island of Anguilla, is 38 km.

Sombrero is 1.67 km long north–south, and 0.38 km wide. The land area is 0.38 km2. Originally, when viewed from the sea, the island had the shape of a sombrero hat, but guano-mining operations have left the island with precipitous sides and a relatively flat top that is 12 m above sea level. The surface of the island is rough, and vegetation is sparse.

The guano-mining operation yielded some 3000 tons of phosphate a year by 1870. By 1890, the phosphate reserves had been exhausted.

As a result of the Treaty of Utrecht in 1714, Sombrero passed into the hands of the British. Captain Warwick Lake of Recruit marooned an impressed seaman, Robert Jeffrey, there on 13 December 1807. As it turned out, Jeffrey survived. A passing American vessel, the schooner Adams from Marblehead, Massachusetts, had rescued him. Still, a court-martial dismissed Lake from the Royal Navy.

In 1814, and again in 1825, a British geologist surveyed the island and found that it abounded in guano and reported this to the British government.

In 1856 the Americans claimed the island, and in a very short period of time quarried 100,000 tons of phosphate that served as fertilizer for the exhausted lands of the Southern States. Uniquely, an important insurrection occurred when West Indian black workers revolted against the “slavery proclivities” of a white American superintendent vis-à-vis wage-earning free men. Four of the 200 workers "fatally injured" Superintendent Snow and commandeered the island and company money and stores.

The British later intervened and demanded compensation from the United States for the occupation. The conflicting claims to the island were settled in Britain's favour in 1867.

Sombrero, lying in the route of shipping from Britain to South and Central America, lay in an area with many hazards and in 1848 the Admiralty was asked to install a light on it. On 30 June 1859, the Royal Mail Steam Packet Company's ship Paramatta was wrecked on her maiden voyage on Horseshoe Reef, which resulted in another request to the Admiralty. The lighthouse was then built and first exhibited its light on the evening of 1 January 1868.

Coincidentally, Paramatta and the Lighthouse built following her demise were both constructed by the same shipyard, the Thames Ironworks and Shipbuilding Company, on the banks of the River Lea in Blackwall, London. Paramatta was the last ship launched from their Middlesex bank, while the lighthouse was built on the Essex side, the yard occupying premises on either side of the river. In 1871, the lease of the island was sold for £55,000 and then sold again for £110,000 to the New Sombrero Phosphate Company, which led to litigation in Erlanger v. New Sombrero Phosphate Co (1878) 3 App Cas 1218.

From the early 1870s until 1885, a Cornish mining engineer, Thomas Corfield, was Superintendent of Sombrero. His duties included organizing the transport of the guano to a spot which was convenient for loading the lighters to take the guano to the ships lying off the island, overseeing the construction of derricks and engine houses, and arranging for the laying of the tram lines for the wagons, which were loaded at the quarries. The guano was just piled in dumps near the engine houses and derricks. There was no semblance of a port and no beach.