Roncador Mountains, mountain range in central Brazil. It has an average elevation of about 1,800 feet (550 metres) above sea level. It extends north-south for about 500 miles (800 km), roughly paralleling the Araguaia National Park to the east. From its western slopes flow the headwaters of the Xingu River; from its eastern flanks come tributaries of the Mortes and Araguaia rivers.