From Halopedia, the Halo wiki
Ridgeline is a multiplayer map included in Halo: Combat Evolved Anniversary for Halo: Reach. It is a remake of Timberland from the PC port of Halo: Combat Evolved, with several alterations to map layout.
The map is set in a former UNSC staging area on a cliff overlooking an enormous Forerunner relay complex. Toward the end of the conflict on Installation 04, the Marine resistance in the area was wiped out by Covenant forces.
The following are locations on the map that are so named on the player's heads-up display during gameplay: