The siting of military and law enforcement land uses is a critical component of spatial planning and urban civil defense, as the improper location of these facilities can increase infrastructural vulnerability, restrict access, and disrupt crisis management. This study aims to determine optimal zones for the establishment of law enforcement infrastructure in the city of Semnan. The research is applied in nature and follows an analytical methodology. The study area encompasses the physical and legal boundaries of Semnan city, covering 7,036 hectares. Spatial data, including road networks, faults, rivers, mines, slope, and other natural, physical, and functional criteria, were processed within a Geographic Information System (GIS) environment. To enhance analytical precision, vector data were converted into a 30×30 meter resolution raster grid, and over 78,000 spatial cells were evaluated. Subsequently, the Analytic Network Process (ANP), fuzzy logic, and continuous membership functions were employed to standardize and weight the criteria, and information layers were integrated into a composite model. The results indicate an asymmetric and limited distribution of suitable land in Semnan. Approximately 61.71% of the city’s area falls within “unsuitable” and “very unsuitable” classes, whereas “highly suitable” zones account for only 1.73% (approximately 121.77 hectares). These zones are primarily concentrated in new urban developments, near ring roads, and along major arterial routes. Proximity to existing law enforcement centers, access to major roads, and distance from residential areas were identified as the most significant decision-making criteria. The findings emphasize the necessity of protecting suitable land and utilizing GIS, ANP, and fuzzy modeling for forward-looking urban planning and enhancing urban resilience.