Map of Middle Earth
This map probably modeled on the West coast of Britain was where the Lord of the Rings saga took place. That Saga took place in a world already invented in the Silmarillion. (http://en.wikipedia.org/wiki/The_Silmarillion). Tolkein was however not just an explorer of space but also time, as he was experimenting with Dunne’s ideas of multi-dimensional time, and each character has a slightly different understanding of time in Lord of the Rings.
For more on that see
Time in the Stone of Suleiman
by Verlyn Flieger
The rhetoric of vision: essays on Charles Williams
By Charles Adolph Huttar, Peter J. Schakel p.75
So Lord of the Rings is also a map of time.
See also . . .