The realm was a perfectly conical mountain over 30,000 feet (9,100 meters) tall. Its peak was permanently obscured by stormy clouds. The mountain interior was riddled with tunnels and passages that opened to the surface to let natural light in, perfectly straight halls and corridors that looped and bent as they followed the mountain's curvature.
All entries into the mountain were extremely well defended by einheriar patrols and by carefully laid out traps. At the same time, the realm was very welcoming to visitors, who were nevertheless kept under close watch. The realm had numerous forges, armories, and shops that provided works of excellent quality.
A single city spanned the entirety of the realm. It was divided into nine districts that more or less specialized in different activities, such as healing or mining. The lowest halls were the city's unsavory underside, where darker and more violent dealings took place.
All inhabitants of Mount Clangeddin were trained for battle. The realm's petitioners and einheriar were frequently sent out to raid the Lower Planes, in particular Acheron, to fight against their old enemies, the goblins and orcs. Unlike in other planes, petitioners who died outside of Mount Clangeddin did not fade into nothingness, but had their essence returned to the plane of Arcadia.
- Colin McComb (February 1995). “Arcadia”. In Michele Carter ed. Planes of Law (TSR, Inc), pp. 15–17. ISBN 0786900938.
- Jeff Grubb, Bruce R. Cordell, David Noonan (September 2001). Manual of the Planes 3rd edition. (Wizards of the Coast), pp. 130–132. ISBN 0-7869-1850-8.
- Colin McComb (October 1996). On Hallowed Ground. Edited by Ray Vallese. (TSR, Inc.), p. 172. ISBN 0-7869-0430-5.
- Eric L. Boyd (November 1998). Demihuman Deities. Edited by Julia Martin. (TSR, Inc.), p. 49. ISBN 0-7869-1239-1.
- Colin McComb (February 1995). “Arcadia”. In Michele Carter ed. Planes of Law (TSR, Inc), p. 16. ISBN 0786900938.
- Colin McComb (October 1996). On Hallowed Ground. Edited by Ray Vallese. (TSR, Inc.), pp. 79–80. ISBN 0-7869-0430-5.
- Wolfgang Baur (February 1995). “Mount Celestia”. In Michele Carter ed. Planes of Law (TSR, Inc), pp. 18–19. ISBN 0-7869-0093-8.