) are an archipelago off the south western tip of the Cornish peninsula of Great Britain.
It is the southernmost location in England and the United Kingdom, as well as the most westerly in England.
The adjective "Scillonian" is sometimes used for people or things related to the archipelago.
The Duchy of Cornwall owns most of the freehold land on the islands.
Rising sea levels flooded the central plain around 400–500 AD, forming the current 55 islands and islets, if an island is defined as "land surrounded by water at high tide and supporting land vegetation".
The population of all the islands at the 2011 census was 2,203.
Scilly forms part of the ceremonial county of Cornwall, and some services are combined with those of Cornwall.
However, the archipelago itself does not contain much tin—it may be that the islands were used as a staging post.
It is likely that until relatively recent times the islands were much larger and perhaps joined together into one island named Ennor.
However, since 1890, the islands have had a separate local authority.
Since the passing of the Isles of Scilly Order 1930, this authority has had the status of a county council and today is known as the Council of the Isles of Scilly.
Tourism is a major part of the local economy, along with agriculture — particularly the production of cut flowers.
Scilly has been inhabited since the Stone Age, and until the early 20th century its history had been one of subsistence living.