Jieznas is a small city in the Prienai district municipality, Lithuania. It is located 16 km (9.9 mi) east of Prienai along the northern shores of Lake Jieznas. Jieznas was first mentioned in written sources in 1492 as property of the Grand Duke of Lithuania. In 1633, the settlement was acquired by the Pac family. They sponsored construction of a church, which was reconstructed in Baroque style in 1768–1772.