Tolkien said that his Middle-earth is our Earth, but in a fictional period in the past, estimating the end of the Third Age to about 6,000 years before his own time. The history of Tolkien's Middle-earth is divided into several Ages. The novel The Hobbit and the main text of The Lord of the Rings deal exclusively with events toward the end of the Third Age and conclude at the dawn of the Fourth Age, while The Silmarillion deals mainly with the First Age.
Middle Earth has a mountain range that seperates its east and west sides called the Misty Mountains. The west of Middle Earth contains areas like the Shire, Rivendell and Bree. The east contains Rohan, Mordor and Gondor. There are more humans to be found on the east side of Middle Earth. Middle Earth is surrounded on three sides by an ocean and on another side, there is a big desert.