Rio Grande do Sul (RS), the southermost State of Brazil Some photos of the RS, diverse localities. Algumas fotos do RS, diversas localidades Despite been mainly rural for much of its early history, Rio Grande do Sul served as the launching pad for several wars Brazil waged against its southern and western neighbors. It also was a focal point for internal rebellion in the 19th century. Rio Grande do Sul's population consists primarily of the descendants of European immigrants, especially Portuguese, Italians, Spaniards, and Germans.