Seyhan is a municipality and district of Adana Province, Turkey. Its area is 444 km2, and its population is 795,012 (2022). It forms the core of the Adana urban area. Seyhan is home to 35 percent of the residents of Adana Province and almost half of the residents of the city of Adana. It is the fifth most populous metropolitan district in Turkey.

Adana Province is a province and metropolitan municipality of Turkey located in central Cilicia. The administrative seat of the province is the city of Adana, home to 78.25% of the residents of the province. Its area is 13,844 km2, and its population is 2,274,106 (2022), making it the sixth most populous province in Turkey. It is also closely associated with other Cilician provinces of Mersin, Osmaniye, and (northern) Hatay.