City of Celestis
From The Stargate Omnipedia
A great golden fortress that lies amid the Plains of Celestis, which may serve as a sort of capital city for the followers of the Ori and the religion of Origin on a planet in their home galaxy.
The chambers of the Doci and the Flames of Enlightenment exist within, as well as a reception area containing a large, hard-bound copy of the Book of Origin.
KEY EPISODES
Origin - Daniel and Vala are taken to the city of Celestis by an Ori Prior.
Stargate: The Ark of Truth - Daniel and Vala are captured and taken to the city, and a wounded Teal'c walks over mountains and across the plains to the city to find them.