Sumy (Ukrainian: Суми [ˈsumɪ]) is a city of regional significance in Ukraine, and the capital of Sumy Oblast. The city is situated on the banks of the Psel River in northeastern Ukraine with a population of 259,660 according to the 2021 census, making it the 23rd-largest in the country. The city of Sumy was founded in the 1650s by the Cossacks within the region of Sloboda Ukraine.