Santo Ângelo is a city located in northwestern Rio Grande do Sul state, Brazil. City population is about 76,304 inhabitants (according to 2010 IBGE census) and the total area of the municipality is about 677 km². Neighboring city Giruá sits to the north and to the south of Santo Ângelo is the city of Entre-Ijuís both linked to the city by state road RS 344.
The local agri-economy produces and deals in soy, corn, wheat, swine, sheep and cattle. Tourism in the city is primarily associated with the city's Jesuit history and the Jesuit Reductions in nearby São Miguel das Missões. The Angelopolitana Cathedral in downtown Santo Ângelo is the seat of the Roman Catholic Diocese of Santo Ângelo.
The city is served by Sepé Tiaraju Airport.
Santo Ângelo was founded on August 12, 1706 by the Jesuit Diogo de Haze. The original name of Santo Ângelo was "Sant’Angel Custódio" and then "Santo Ângelo Custódio." The Reduction of Santo Ângelo was dedicated to the "Anjo Custódio das Missões", the guard and protector of the missionaries or Jesuits.
The Angelopolitana Cathedral in Santo Ângelo, Rio Grande do Sul, was built in the 1920s on the same spot as the Santo Ângelo reduction built by Jesuits and the Guarani in the 18th century—the Cathedral is modeled after the ancient São Miguel das Missões mission also known as São Miguel Arcanjo.