Map - Riosucio, Chocó (Riosucio)

Riosucio is a municipality and town in the Department of Chocó, Colombia. The municipality and town are located in the Atrato River basin, on the Chocoan side of Urabá, a region spanning the departments Chocó and Antioquia.

Riosucio municipality is landlocked, being separated from the Pacific Ocean by the Chocoan municipalities Juradó and Bahía Solano and from the Gulf of Urabá, a large inlet of the Caribbean Sea, by the Antioquian municipality Turbo and the Chocoan municipality Unguía. Riosucio town is mostly inaccessible by roads and has no airport; the river is the main route for access to and transportation within the town.

Before the Spanish arrival in the region now known as Chocó, the region was populated by indigenous Emberá and Katío communities. Spanish exploration began in 1501, with Rodrigo de Bastidas, Vasco Núñez de Balboa, and Juan de la Cosa making the first efforts. There are no exact data on the foundation of Riosucio, but it could have occurred between 1518 and 1524, after Vasco Núñez de Balboa's second trip to the Atrato River. Although Spanish invaders tried to gain control of the area, the indigenous population kept them away until the 18th century, when an increase in trade and the region's presence along potential north–south trade routes made the region again of interest to colonizers.

The municipality and town are named Riosucio (in English "Dirty River") after the river of that name that joins the Atrato River. The town was founded by the Spaniard Domingo Bailon.

In 1996, the town was the target of a violent operation of the Colombian military along with paramilitary groups, in response to organizing by Afro-Colombians and the subsequent law granting land rights to residents of Riosucio and other nearby towns. Hundreds were killed, many disappeared, and over 22,000 survivors were forced to leave their lands and move to poor neighborhoods of big cities around the country.