Seyitgazi is a municipality and district of Eskişehir Province, Turkey. Its area is 1,578 km2, and its population is 12,587 (2022). The central town of Seyitgazi lies at a distance of 43 km (27 mi) towards the south from the province capital of Eskişehir. The town was known formerly as Nakoleia.

Eskişehir Province is a province and metropolitan municipality in northwestern Turkey. Its area is 13,960 km2, and its population is 906,617 (2022). Its adjacent provinces are Bilecik to the northwest, Kütahya to the west, Afyon to the southwest, Konya to the south, Ankara to the east, and Bolu to the north. The provincial capital is Eskişehir. Most of the province is laid down in Central Anatolia Region. Northern parts of Mihalıççık district and ones of Mihalgazi and Sarıcakaya are located in the Black Sea Region and one of them belong to the Aegean Region.