The photointerpretation of an area of 105,400 ha, corresponding to the County of Castilho in the uppermost northwest of the State of São Paulo was made and the corresponding map elaborated. In 1962, upon taking the air pictures, the soils were covered as follows : 9.5% with forests, 63.8% with grassland, 15.8% with several crops, 0.8% with "banhado", 3.1% with residual cover, 0.1% representing an urban area, 2.3% were covered with water and only a small area of 10 ha had been reforested with eucalyptus. The greatest part of the mapped soils is originated from fluvio-lacustrine deposits of the Cretaceous, called "arenito de Baurú". An expressive area of hydromorphic or alluvial soils occurs, represented by flatland of the rivers Paraná and São José dos Dourados, in its greatest part still in "banhados".