On the site are the remains of an Iron Age village, two entrance graves, prehistoric field systems, standing stones, post-medieval breastworks, and a Victorian kelp pit.

At the top of the hill, on its southwestern border and overlooking the coastal inlet between St. Mary's and Tresco Island, lies the Bronze Age entrance grave, Bant's Carn.

[3] The remains of the ancient village show evidence of continuous settlement from the prehistoric to the Roman period in Britain.

[4] Between the Bronze Age grave and the ancient settlement are the remnants of prehistoric field systems that are discernible as a sequence of terraces and raised banks.

Behind the cliff's edge, there is a line of low bank and ditch fortifications, built in the mid-seventeenth century and in use during the English Civil War.

From the late seventeenth to the early nineteenth centuries, soda-ash was manufactured on Halangy Down in a stone-lined kelp pit.

Archaeological excavations conducted in 1935, 1950, and 1964 to 1970, revealed that the first stone structures were built during the Iron Age (800 BC - 100 AD).