Boo (Asturian and official name: Bo [1]) is one of 18 parish (administrative division) in Aller, a municipality within the province and autonomous community of Asturias, in northern Spain.
The altitude is between 420 m (1,380 ft) and 480 m (1,570 ft) above sea level. It is 6.9 km2 (2.7 sq mi) in size with a population of 529 (INE 2008).