This lecture is an exploration of the archipelagic island imagination of artist, poet and writer Brenda Chamberlain (1912–71) under the rubric of literary cartography. Part of a wider study of the literary text's 'mapmindedness' – the ways in which imaginative writing accomplishes specifically cartographic 'work' – the paper examines Chamberlain's emotional geographies of the Irish Sea, focusing on her fabling autobiographical account of her residence on Bardsey Island (Ynys Enlli), off the Llyn Peninsula, north Wales: Tide-race (1962).