Nin is a town in the Zadar County of Croatia. Nin was historically important as a centre of a medieval Christian Diocese of Nin. Nin was also the …Nin is a town in the Zadar County of Croatia. Nin was historically important as a centre of a medieval Christian Diocese of Nin. Nin was also the seat of the Princes of Dalmatia. Nin's historical center is located on an islet only 500 meters in diameter. Nin is situated in a lagoon on the eastern shore of the Adriatic Sea, surrounded by natural sandy beaches and linked with the mainland by two stone bridges from the 16th century.