The island is rich in built remains from the Iron Age, though they are generally in poor condition. A number of small island forts can be found throughout Benbecula, particularly on Loch Olabhat, but the most substantial is Dun Buidhe, near Balivanich, which has a series of causeways linking it to the loch shore, via Eilean Dubh ("Black Island"); a wheelhouse was also present nearby (a better preserved wheelhouse survives on the adjacent island of Grimsay), at which Iron Age pottery was found.