Events that occurred on 18 March
 On Earth
- 1941 - J.R.R. Tolkien writes Letter 44.
- 1950 - Actor Brad Dourif is born.
- 1956 - Tolkien writes a letter to a Mr Sam Gamgee.
- 1971 - Tolkien writes Letter 322.
- 2005 - "Black Rider", the twelfth set in The Lord of the Rings Trading Card Game, is released.
- 2008 - The Lord of the Rings Online: Mines of Moria is announced.
 In Arda
- T.A. 2510:
- T.A. 3019:
- The Host of the West marches from Minas Tirith. After Osgiliath, they end the day march but a vanguard continues to the Cross-roads. Aragorn reclaims the land and retores the defiled statue of the King.
- Frodo comes in sight of the Isenmouthe. He is overtaken by Orcs on the road from Durthang to Udûn.