The Municipality of Nikaia-Agios Ioannis Rentis is located in the Attica Region, specifically in the administrative district of Piraeus within the Attica Region, and lies in the southwestern part of the Urban Complex of Athens. According to the provisions of Law 1515/85 "Spatial Plan for the Environmental Protection of Athens," it falls under the spatial subunit of the Athens Basin. It is considered one of the largest municipalities in the Attica Region, extending at the foothills of Mount Aigaleo, and holds a pivotal position between Athens and the large port of Piraeus. According to the Strategic Spatial Development Plan, it is classified as a Municipal Center for Overregional Activities.
