The Big Horn River was a river which flowed through the Military Wilderness Training Preserve in the Highland Mountains in the continent of Eposz, Reach.[1]


The Spartan-IIs used the river for training exercises, as they knew the terrain well and could navigate it easily.[2]

Human-Covenant warEdit

Main article: Fall of Reach

During the Battle of Reach, a Covenant invasion force of more than ten thousand ground troops, supported by a Covenant Cruiser hovering overhead, landed, and set up camp near the Big Horn River. A section of the Big Horn River was evaporated during the Battle of Reach, when Spartans Fred-104, Kelly-087, and Joshua-029 destroyed the invasion force and the Cruiser using a Fury Tactical Nuclear Weapon.[citation needed]


  1. Halo: The Fall of Reach, Page ??
  2. Halo: First Strike, Page 157