Dundonald Castle is a stern medieval tower on a hill above Dundonald village, northeast of Troon. The present castle was built around 1371 for Robert Stewart, who soon after became King Robert II, and its bare stone shell still has enough scale to make the climb worthwhile.
It is a compact visit rather than a full-day castle, but the site gives a good sense of Ayrshire's older history beyond Burns country and the coast. The hilltop position also brings wide views over the surrounding countryside on a clear day.