Júlio de Castilhos is a municipality of the western part of the state of Rio Grande do Sul, Brazil. Its area is 1,120.8 km² and its population was 3,571 in 2003. Its elevation is at 529 m (Praça "João Vieira de Alvarenga"), 516 m at the meteorological station and 503.81 m at the railway station. The origin of the name comes from the Tupi language. It is located 627 km west of the state capital of Porto Alegre, northeast of Alegrete.