Neris ( Belarusian: Ві́лія Viliya, Polish: Wilia) is a river rising in Belarus, flowing through Vilnius (Lithuania) and becoming a tributary of the Neman River (Nemunas) at Kaunas (Lithuania). Its length is 510 km.
275 km of the river runs through Belarus, where it is called Viliya, and 235 km runs through Lithuania, where it is called Neris.
The Neris connects two old Lithuanian capitals - Kernavė and Vilnius. Along its banks are burial places of the pagan Lithuanians. 25 km from Vilnius are the old burial mounds of Karmazinai. There also are many mythological stones, and a sacred oak.