Rothesay is the principal town on the Isle of Bute, in the council area of Argyll and Bute, Scotland. It lies along the coast of the Firth of Clyde. It can be reached by a Caledonian MacBrayne ferry from Wemyss Bay, which also offers an onward rail link to Glasgow Central Station. At the centre of the town is the 13th-century ruin Rothesay Castle, unique in Scotland for its circular plan.