Burgh Island is a tidal island on the coast of South Devon in England near the small seaside village Bigbury-on-Sea. There are several buildings on the island, the largest being the Art Deco Burgh Island Hotel. The other buildings are three private houses, and a pub, the Pilchard Inn, parts of which date to the 14th century. The island is strongly associated with writer Agatha Christie, who often visited and used the island and its hotel as a setting and inspiration for two famous novels: And Then There Were None (1939) and Evil Under the Sun (1941).

Archaeological discovery of tin ingots at the River Erme estuary wreck show that the local area was a significant tin trading port in ancient times; it is unclear whether the ingots date from the Iron Age or Sub-Roman periods, however this discovery so close to Burgh Island has drawn comparisons with Diodorus Siculus's 1st century BCE text, more often associated with St Michael's Mount in Cornwall:

At this time we shall treat of the tin which is dug from the ground. Those who dwell near Belerium, one of the headlands of Britain, are especially fond of strangers, and on account of their trade with the merchants they have a more civilised manner of living. They collect the tin after the earth has been skillfully forced to yield it. Although the land is stony, it has certain veins of earth from which they melt and purify the metal which has been extracted. After making this into bars they carry it to a certain island near Britain called Ictis. For although the place between is for the most part covered with water, yet in the middle there is dry ground, and over this they carry a great amount of tin in wagons [...] Thence the merchants carry into Gaul the tin which they have bought from the inhabitants. And after a journey of thirty days on foot through Gaul, they convey their packs carried by horses to the mouths of the Rhone River.

The island has been known by various names over the years. Early records and maps mention it as St Michael's Island. The name later changed to Borough Island, eventually shortened to Burgh. As late as 1947 an Ordnance Survey map refers to the island as Borough Island. In 1908 a postcard produced by Stengel & Co Ltd of London referred to it as Burr Island. A map published in 1765 shows "Borough or Bur Isle".

It is believed a monastery was established on the island, most of the remains of which may lie beneath the current hotel. The ancient Pilchard Inn's history dates to 1336 and may have started life as the guest lodgings for the monastery.

A small, possibly transient, population of fishermen occupied the island following the dissolution of the monastery, specialising in pilchard fishing. There are the remains of a chapel atop the island, which later became a "huers' hut" — a place where fishermen would make a hue and cry call to inform other fishermen of shoals of pilchards. During this period, smuggling, wrecking, and piracy were common, benefiting from a natural barrier for half the day.

Fear that German landing forces might use the island as a beachhead during World War II resulted in the area's fortification with anti-tank defences and two pillboxes, positioned on both sides of the causeway. An observation post was also established on the summit to monitor the coastline.

A beach house was built for Agatha Christie as a writer's retreat and still exists on the island.