Loudoun Hill is a volcanic plug in East Ayrshire, Scotland. It is located near the head of the River Irvine, east of Darvel. The A71 Edinburgh - Kilmarnock road passes by the base of the hill. This route follows a Roman road which linked the Clyde Valley with the Ayrshire coast. Loudoun Hill's position at the highest point on this route gives it huge strategic signif…Loudoun Hill is a volcanic plug in East Ayrshire, Scotland. It is located near the head of the River Irvine, east of Darvel. The A71 Edinburgh - Kilmarnock road passes by the base of the hill. This route follows a Roman road which linked the Clyde Valley with the Ayrshire coast. Loudoun Hill's position at the highest point on this route gives it huge strategic significance. The hill stands above moorland, and commands 360-degree views. On clear days the coast, 40 km away, and the Isle of Arran beyond, are visible.