Trostianets, also known as Trostyanets, is a city located in the Okhtyrka Raion of the Sumy Oblast in northeastern Ukraine. Situated on the Boromlya River, the city is positioned approximately 59 km (37 mi) from Sumy. It previously served as the administrative center of the Trostyanets Raion until that district was abolished on July 18, 2020.
The city has a population of 19,544 and features several notable historical landmarks. These include the neo-Gothic "Round Courtyard" dating back to 1749, the late Baroque Church of the Annunciation built between 1744 and 1750, the 18th-century Galitzine Palace, and a site known as the "Grotto of the Nymphs."