Santa Cruz do Sul is a Brazilian municipality located in the central region of the state of Rio Grande do Sul. It is situated approximately 155 kilometres (96 mi) from the state capital, Porto Alegre, and covers an area of 733.4 square kilometres (283.2 mi2). According to estimates by the Brazilian Institute of Geography and Statistics (IBGE), the city had a population of 138,104 in 2024, ranking it as the 14th most populous municipality in the state.
The city is located within the Vale do Rio Pardo region and borders the municipalities of Vera Cruz, Rio Pardo, Sinimbu, Venâncio Aires, and Passo do Sobrado. Geographically, it lies in a physiographic transition zone between the Brazilian Highlands and the Central Depression. The area features a temperate climate and diverse vegetation from both the Atlantic Forest and the Pampas, with a predominance of volcanic rocks.