Neris (About this sound pronunciation , Belarusian: Ві́лія Viliya, Polish: Wilia) is a river rising in Belarus. It flows through Vilnius (Lithuania) and becomes a tributary of the Neman River (Nemunas) at Kaunas (Lithuania). Its length is 510 km (320 mi).For 276 km (171 mi) the river runs through Belarus, where it is called Viliya, and 235 km (146 mi) runs through Lithuania, where it is called Neris.The Neris connects two old Lithuanian capitals – Kernavė and Vilnius.