The Vorskla River, located in Russia and northeastern Ukraine, is a south-flowing tributary of the Dnieper River.
An ancient fort, thought to be Gelonos, is on the Vorskla south of Okhtyrka. In 1399, the Battle of the Vorskla River was fought in the area. In 1709, the city of Poltava, on the banks of the Vorskla River, was besieged by Charles XII.
It has a length of 464 kilometres, a basin area of 14,700 square kilometres and is mostly navigable between its delta and Kobelyaky.
Wikipedia https://en.wikipedia.org/wiki/Vorskla_River
Coordinates 49°45'55.858" N 34°37'9.485" E