The Río Nentón is a river in Guatemala. From its sources in the Sierra de los Cuchumatanes of Huehuetenango, the river flows in a north-westerly direction, crosses the border with Mexico at 15.797705°N 91.891150°W (Río Seleguá) and joins the Río Seleguá which continues northwards to the Presa de La Angostura, one of Mexico's largest artificial lakes.