Ghost Town

Almost nothing is known except that it is asymmetrical and it is a small map. It had its lighting "changed considerably" to better fit the "death-at-sunset feel." The level has been described as a bridge between nature and failed human civilization. It is reported to have many levels, open air catwalks with sights down to semi protected alleys where you can "rain death from above".

This map's codename was O.K. Corral.

The name is a reference to the Gunfight at the O.K. Corral. Much like Bungie said perfect for medium and close range battles.

Extracted from an interview describing the location: "Ghost Town is the fragmented ruins of a small 24th century water purification complex that geographically lies just North and West of the jungle foothills hydroelectric facility from the Sierra 117 mission. The well-protected facility built into a shallow ravine was once home to the Global Water Campaign, where the still somewhat-pure Kilimanjaro meltwater was transported via pipelines from the river and directed to this small outpost where it became further purified, and then transported via GWC trans-African pipelines along the Tsavo Highway for distribution throughout the entire continent."

- Vic DeLeon, artistic designer

Speculation
With the fact of the catwalks, it was speculated that it was a remake of one of the Halo 2 Multiplayer maps Turf or Tombstone as both featured catwalks, second stories and several alleys. This was proved to be false as it was stated on 02/04/08's Bungie Podcast that O.K. Corral, Purple Reign, and Cottonball are original maps. Bungie's mention of nature encroaching on failed civilization may imply that the level will be thematically designed after the jungle of Sierra 117 (level), similar to how Rat's Nest (level) was based on Crow's Nest (level).

Info on bungie.net http://www.bungie.net/News/content.aspx?type=topnews&cid=13287