Coastal areas offer great recreational and economic opportunities, but require intensive resource management and environmental protection. Land use and land cover information provides a rapid and cost-effective means for monitoring and planning coastal area development. This study quantitatively describes spatiotemporal changes of land use and land cover over the last four decades in a coastal area of the state of Rio de Janeiro, Brazil. Historical aerial photographs from 1976 and satellite images from 1990 and 2012 were classified and analyzed. We used supervised classification and machine learning techniques to classify the images. An accuracy assessment of results was performed. Land use change statistics for the period indicate that urban areas have increased to the detriment of dense vegetation, salines, and bare soil. The analysis provides a basis for better control of anthropogenic impacts and geoconservation activities in this coastal area of Rio de Janeiro.