Illano is one of four parishes (administrative divisions) in San Martín de Oscos, a municipality within the province and autonomous community of Asturias, in northern Spain.It is 7.29km2 in size, with a population of 17 (INE 2006).Villages and hamlets Arruñada (A Arruñada) Arne (El Arne) San Pedro de Ahio (San Pedro Io)