Zwolle (zwôlˈə) [key], city (1994 pop. 99,139), capital of Overijssel prov., N central Netherlands, on the Zwartewater River. It is an administrative, transportation, and industrial center. Shipbuilding and iron-working are activities. Notable buildings include the 15th-century town hall and the Church of St. Michael, a 15th-century Gothic structure. Nearby was the monastery where Thomas à Kempis lived (15th cent.).