Mastaura Ancient City is located 3 km from the Nazilli District of Aydın Province. It is situated in a narrow valley that extends between the Bozyurt and Eycelli Districts to the north. This city, positioned on the natural route that runs along the Büyük Menderes Valley and connects the Aegean coast to the interior of Anatolia, had its origins in the coastal cities of Miletos and Ephesos in the west during ancient times. It continued through Tralleis and Nysa, and extended from Hierapolis and Laodikeia towards Anatolia in the east. It became one of the significant cities along the Caput Via road, which extends into the interior.
Additionally, the city is strategically located at a crossroads within its regional geography. Across from the city, on the other side of the plain, lies the Harpasos Stream (Arpas Stream/Kemer Stream), and the valley stretching along this stream serves as an important route connecting the Caria interior to the Maiandros plain. Similarly, right next to Mastaura, approximately 6 km to the east and extending northward through the Mesogis (Aydın Mountains), you'll find the Kestel Valley. This valley serves as a natural route that allows passage from the interior of Lydia to the Maiandros plain. Therefore, the city's location at the intersection of roads coming from the Caria Region in the south and the Lydia Region in the north, as well as its position on the main east-west axis road along the Maiandros (Büyük Menderes River), highlights the significant importance of Mastaura within the region.