Santa Maria is a municipality in the central region of Rio Grande do Sul, the southernmost state of Brazil. In 2025, its population was 282,395 inhabitants in a total area of 1,823 square kilometres.
BR-158 is a federal highway of Brazil. One of the longest highways in the country, the 3,955.0-kilometre road connects Altamira, Pará, to Santana do Livramento on the Uruguayan border where it joins R