It rises in the Mantiqueira Mountains in the state of Minas Gerais and descends inland, west-northwestward.

Its lower course marks a portion of the Minas Gerais-São Paulo border.

The river plays a major role in production of electricity and, due to rapids and waterfalls, and absence of locks, is only navigable by small craft in limited stretches.

The EFOM met the Rio Grande at Ribeirão Vermelho, from where the service ran down the river for 208 km (129 mi), as far as Capetina.

There were six stations on the river between Ribeirão Vermelho and Capetinga, and the railway operated a fleet of 6 stern-wheel paddle steamers, together with barges and launches.