Cities that have been continuously inhabited and embody the spatial traces of historical continuity are defined as “multi-layered”. The remnants of historical periods and cultures, which constitute the stratified layers of the city and the interconnections among them, contribute to the spatial complexity and identity of multi-layered cities. However, when these remnants are not perceivable or effectively integrated into the contemporary city, the conservation and long-term sustainability of multi-layeredness become increasingly challenging. This necessitates the documentation of historical layers and the synthesis of fragmentary information from diverse sources into a coherent and systematic framework. Thus, the aim is to make the components of different historical periods in various parts of the city known, and to understand and evaluate their relationship with the contemporary city both vertically and horizontally. Ankara, inhabited since prehistoric times and characterized by being a multi-layered city, was chosen as the study area. To produce comprehensive and usable information, Geographic Information Systems (GIS) were utilized. GIS facilitates the processing of complex and voluminous data from diverse disciplinary sources. "MULAAN▪GIS [MUlti-LAyered ANkara GIS]" was produced by processing historical period components into the database, together with the attributes of the identity areas representing their period. This approach unveiled historical continuities and discontinuities, the physical, functional, visual, and intellectual integration levels, along with the challenges faced by citizens. The historical spatial dataset and integration degrees created in the GIS have the potential to serve as a spatial decision support system on heritage protection, thereby providing an input for spatial plans.