Lutsk, city, northwestern Ukraine, on a defensive site at a bend in the Styr River. It was a tribal settlement, perhaps of the Luchanians, as early as the 10th century. The first known record of the settlement dates to 1085. Lutsk later became a part of the principality of Galicia-Volhynia and until the late 18th century was in Lithuania-Poland, when it fell into Russian hands. It belonged to Poland again in 1919–39. The older part of the city contains the 14th-century castle of the Lithuanian prince Liubartas and much old architecture. Three monasteries date from the 16th to the 18th century. An automobile plant was constructed in the city in the late 1970s to build the Volynyanka, a multipurpose vehicle for rural use. Other economic activities in Lutsk have included the production of scientific instruments and food. A teacher-training institute and a medical school are located there. Pop. (2001) 208,816; (2005 est.) 202,915.