Boal (written Boal according to the reintegrationist and isolationist writing norms and Bual according to the Occidental Asturian spelling) is a municipality, a civil parish and a town in the Autonomous Community of the Principality of Asturias (Spain). It borders north with El Franco and Coaña, south with Illano, west with Castropol and east with Villayón.The main way of access to the municipality is the regional road AS-12, which connects Navia with Grandas de Salime.