Dun an Aird, Eilean na h-Ordaig occupies the summit of a low rocky knoll on the tidal islet on the Isle of Mull, just off the North shore of Loch Scridain. On the South-West the dun is protected by a rock face about 8 eight feet high, but on all other sides the dun can be approached over level ground or shallow shoreline.

Roughly circular on plan, the dun measures approximately 45 feet in diameter within a dry-stone wall from eight to 13 feet thick. The wall now appears as a largely grass covered stony bank, which stands at least 6 feet above the level of the interior. The line of the inner face can be traced round most of the perimeter. There are two entrances, situated on the Northwest and Southeast sides.

The dun has been further protected by a stone wall drawn in an irregular curve round the Northeast half and continues along the edge of the low cliff.  This outer wall now appears in most places as a stony scarp up to 3 feet high.

The dun was built around 2000 years ago as small extended family defensive settlement, located on a small low island with excellent access to the sea which provided both its primary means of access and also defence. It was eventually abandoned for more comfortable accommodation with land to cultivate on higher ground along the shoreline.

The dun can be accessed by a relatively short walk across very boggy ground criss-crossed by small streams, so making your way to the dun requires careful footing and waterproof boots!