Osgiliath (‘Fortress of the Stars’) was once the chief city of ancient Gondor. It was located on the River Anduin, about fifteen miles North-east of where Minas Tirith stood.

Elendil and his sons founded the city during the end of the Second Age, and both the thrones of Anárion and Isildur were located in Osgiliath’s Great Hall. The most powerful of the Palantíri, the Stone of Osgiliath, was located there.

The plague of the mid-Third Age left most of Osgiliath deserted and King Tarandor moved the throne of the King of Gondor to Minas Anor. The city began to decay, and almost seven hundred years later, Sauron’s forces finally destroyed Osgiliath completely.
Encyclopedia entry originally written by Ringhilwen