King Henry I gave it to Tavistock Abbey which established a priory on Tresco; it was abolished during the Dissolution of the Monasteries.

[10] A variety of scenery is found on the island, including rugged granite outcrops, heathland of the exposed north coast and mainly shell beaches in the east and south.

Combined, their facilities include a convenience store (with a post office sub-branch), an art gallery, a pub, and two café/restaurants, all of which are owned and run by the Tresco Estate.

Unlike the other Scilly islands, Tresco is primarily run as a holiday resort,[14] and virtually all activity and employment is tourist-related.

Secondary pupils board at the St Mary's main campus,[22] staying there on weekdays and coming back and forth to their home islands on weekends.

[26][27] Tresco is unique amongst the off islands in that its habitat ranges from a windswept northern plateau with waved heath to sheltered bulb fields, wetland and lakes, to beautiful beaches backed by a sand dune system on the south coast.

Castle Down is a SSSI for its waved maritime heath, its lichen flora, a breeding colony of Common Tern (Sterna hirundo) and for its geology.

[29] [30] [31] In October 2012, four male and one female Red Squirrel (Sciurus vulgaris), on permanent loan from the British Wildlife Centre, were transported to Tresco by helicopter.

Among the many vagrant birds which have been found here, the following were firsts for Britain: The island also briefly hosted the second British record of Great Blue Heron (Ardea herodias) in April and May 2015, which also visited both Bryher and St Mary's during its 23-day stay.

Because of its geography and history, Tresco has often featured in fiction, most notably in the books of author Sam Llewellyn, a direct descendant of Augustus Smith who, after his appointment as Lord Proprietor of the Scillies in 1834 and living on the island, began to create the Abbey Gardens on land which surrounded the old Priory.