Xingu, river, 1,230 mi (1,979 km) long, rising in central Mato Grosso state, Brazil, and winding north across Pará state into the Amazon River at the head of the Amazon delta. The Xingu, with many rapids and falls, passes through wild, partly unexplored country, and only in its lower course is it navigable. Pioneers have pushed into the area and have settled farms in the forest. The Brazilian government built a hydroelectric project along the river in the 1970s.