When Halo: Combat Evolved Anniversary was announced back at E3 it was said that the multiplayer would build on the foundation of Halo: Reach, but offering up seven classic Halo maps. We have previously known about the new versions of Beaver Creek (now: Battle Canyon) and Damnation (now: Penance), but the rest of the maps where revealed at Halo Fest.
These are Hang 'Em High and Prisoner from Halo: Combat Evolved, Timberland from Halo on PC and Headlong from Halo 3. There will also be a brand new Firefight map called Installation 04 based on one of the areas found in the second mission of the campaign.