Barcelos, (also Barcellos), formerly Mariuá, is a municipality located in the State of Amazonas, northern Brazil. Its population was 32,169 (2005) and its area is 122,476 square kilometres (47,288 sq mi), making it the second largest municipality in Brazil (behind Altamira, Pará), equivalent in size to New York state in the United States and slightly larger than North Korea.