Adana is a large city in southern Turkey. The city is situated on the Seyhan River, 35 km inland from the northeastern shores of the Mediterranea…Adana is a large city in southern Turkey. The city is situated on the Seyhan River, 35 km inland from the northeastern shores of the Mediterranean Sea. It is the administrative seat of the Adana province, and has a population of 1.8 million, making it the largest city in the Mediterrenean Region of Turkey.