This work presents data on deforestation and horizontal expansion of agriculture, calculated for the Toropi-RS river basin, based on thematic maps based on aerial photographs. The data show a significant decrease in natural vegetation and reforestation and an increase in agricultural areas. In the twelve years studied (1964 to 1975), the Subtropical Forest, the Capões, and the areas with eucalyptus had their areas reduced in relative values of 25.51%, 56.03% and 35.62%, respectively, while area increased by 73.75%. The increase of cultivated areas, analyzed by relief compartment, was higher in the downstream compartments (Central Depression and Planalto Border), which from 1964 to 1975 had their agricultural areas increased by 82.38%. The agricultural area of the Plateau, obtained a significant increase,
