The Sura (Russian: Сура́, Chuvash: Сăр) is a river in Russia, a north-flowing right tributary of the Volga. Its mouth on the Volga is about half way between Nizhny Novgorod and Kazan. It flows through Penza Oblast, Mordovia, Ulyanovsk Oblast, Chuvashia and Nizhny Novgorod Oblast. It is 841 kilometres (523 mi) long, and has a drainage basin of 67,500 square kilometres (26,100 sq mi). It is navigable for 394 km from the mouth. The city of Penza, and smaller towns Alatyr, Shumerlya, Yadrin lie along the Sura. At the confluence with the Volga there is a settlement of Vasilsursk.