The present work aimed primarily to carry out a synthesis of the nature of the soil in the town of Djelfa and to develop a database of existing geological and geotechnical data that are available in order to put them at the disposal of all potential users, whether scientific or operational. The carried out work consisted in collecting and organizing the existing geological and geotechnical data on a geographical information system. The criteria were first identified (allowable stresses, allowable depths, etc.) and then maps with the different important factors were developed. Subsequently, these maps were superimposed to arrive, after a succession of generalizations of the geotechnical map, at an official final map with geotechnical terms. The interpretation of the obtained results allows for identifying the contributions and placing limits to the results and then trying to apply this method to other sites presenting similar problems and context. It should be noted that the maps produced are intended to enlighten decision-makers and planners when dealing with areas that are expected to be urbanized. They can also be helpful when conducting a preliminary study before the geotechnical study.