Quarai is a Brazilian municipality located near the border with Uruguay on the Rio Quaraí. The population is 22,607 in an area of 3,147.63 km², …Quarai is a Brazilian municipality located near the border with Uruguay on the Rio Quaraí. The population is 22,607 in an area of 3,147.63 km², making it one of the largest municipalities in the state. Its elevation is 112 m. It is located 590 km west of the state capital of Porto Alegre, northeast of Montevideo, Uruguay and southeast of Alegrete.