Río Colorado is a town and municipality in the Río Negro Province of Argentina. It is the administrative centre of the Pichi Mahuida Depart…Río Colorado is a town and municipality in the Río Negro Province of Argentina. It is the administrative centre of the Pichi Mahuida Department. According to the 2010 census, the municipality 13,828 inhabitants, an increase of 0.12% compared to the 2001 census which recorded a population of 12,900.