Inchcailloch — "island of the old woman" or "of the cowled woman", probably after the Irish saint Kentigerna — lies just off Balmaha and is reached by a small passenger ferry. It's heavily wooded, part of the Loch Lomond National Nature Reserve, and laced with a short nature trail over the island's 85-metre summit.
In the north of the island is the burial ground of the old parish church, used until 1947; it was the burial place of the MacGregors, including some of Rob Roy's ancestors. In the south, Port Bawn has a small sandy bay and campsite. About 20,000 people visit a year.