Trostianets is a city in Sumy Oblast of Ukraine, the center of Trostianetskyi Raion. It's located on Boromlya River, 59 km (37 mi) from Sumy. The city population is 23,300 (2001). The district of Trostyanets has 49 settlements, inhabited by 41,700 people governed by 16 village councils and the town. The city is famous for its old brick factory, which supplied the majority of it building supply.