The War of the Ring was the great war which ended the Third Age of Middle-earth, and in which Sauron was permanently crippled and banished by the (effective) destruction of the eponymous One Ring. The War is generally held to have begun on 20 June 3018 when Sauron's forces simultaneously attack eastern Gondor (Osgiliath) and the Wood-elves of Thranduil; and to have ended with the Battle of Bywater in The Shire on 3 November 3019.
Battles and conflicts in the War of the Ring:
Duel at Dúrin's Tower
Skirmish on Lórien
First Battle of the Fords of Isen
Second Battle of the Fords of Isen
Battle on the eaves of Fangorn
Skirmish at Cirith Ungol
(N) = Non-canon