Gran Rio (English: big river) is a river of Suriname. The Gran Rio confluences with the (English: small river) to form Suriname River. The river runs from the northern hills of the Eilerts de Haan Mountains. It has a stony bottom, forms many tiny islands and has many rapids. At , there are many rapids and waterfalls. The river was first explored in 1908 by Eilerts de Haan to find the source of the Suriname River.