'Lune' is also spelt 'Lhun'.

The Lune was a large river flowing south into the Gulf of Lune, the River Lune drained most of the lands between the Hills of Evendim and the northern range of the Blue Mountains.

The Elf City of Mithlond, the Grey Havens, sat at the mouth of the River Lune.

Fleeing the destruction of Beleriand, Elendil the Tall used the river as his route inland before founding the Kingdom of Arnor.
Encyclopedia entry originally written by PotbellyHairyfoot