Barrancos is a town and a municipality in Portugal. With a population of 1,834 in 2011, it is the least populated municipality in mainland Portu…Barrancos is a town and a municipality in Portugal. With a population of 1,834 in 2011, it is the least populated municipality in mainland Portugal. Its area is 168.42 km². The municipality is composed of one parish, being one of the six Portuguese municipalities composed of only one parish, and is located in Beja District, close to the Spanish border.