Isolation

Isolation is a multiplayer map featured in Halo 3 that takes place at a Flood containment facility on Installation 00. The environment is a small, isolated bio-bubble that has contained the Flood on the Ark. The Milky Way Galaxy hangs in the sky. The top level is grassy and untainted, but in the underground caves, there is an obvious Flood contamination. Its open layout, with two bases, makes it a good map for Slayer, Team Slayer, and symmetrical objective gametypes.

Layout
Despite its regular appearances in Free-For-All and Team Slayer matches, it was designed for symmetrical objective games. It features two symmetrical underground bases, a grassy hilltop above, Forerunner architecture, and the underground caves of Flood biomass.

Topside
Isolation has an ovular shape to it when observed from above. It is a symmetrical map that consists of two levels: above and below. The upper level is a grassy hilltop with Forerunner architecture woven into the terrain. To the north, at the crest of the hill, lies a silver-Grey multi-level Forerunner structure. A battle rifle spawns at either side of this tower. It can be used either for shelter (underneath, where the shotgun spawns) or as a sniper perch (by standing on top). Directly behind this sniper perch is an escape chute that provides quick, one-way access to Isolation's lower level through a Porta. From here, the player can go to his left (east), right (west), or move forward (to the south); the player cannot regain entry to the sniper perch by going back up the chute, not even on a Ghost or Mongoose.

Underground
Going left or right will lead to one of the cave's side entrances. At either entrance is a man cannon, which will blast the player back to the top of the map. Going south will take the player towards the mouth of the cave. Midway through the cave, there is a concrete bunker on either side. The bunkers have portholes for weapons fire. The bunkers can't be entered here. A little further south is where the rocket launcher and Ghost spawn. At the southernmost end of the cave, a thin rock ridge extends upward around the map's wall. This makes for another excellent sniper spot. Directly above the mouth of the cave is another Forerunner structure in the shape of an archway, which is rusted-brown. There is another drop-down here, which will put the player near the Ghost/rockets.

Bunkers
On the east and west sides of the map, in front of the two man cannons, is a Mauler, and next to that an entrance to each of the respective bases. A regenerator exists in the main pylon of each base, as well as a battle rifle, spike grenades, and a Spiker. The player can either take a ramp down or drop in from a hole above. Just above this area is the Brute Shot, a battle rifle, frag grenades, and a Mongoose.

Changes For Matchmaking
Isolation has been slightly altered for Matchmaking. The only immediately noticeable change is the removal of the flare from the Silver Structure on Topside. Flares now no longer occur in any matchmaking game.

Strategies

 * Rushing for the Ghost and the rocket launcher at the beginning. However, also camping beside either of the two and waiting for others to ambush as they attempt to pick them up is also a good tactic if used well.
 * Isolation is a very unpredictable map. Try to assume how opponents will attack and surprise them with bold moves.
 * If sniping is a preferred tactic, taking the sniper rifle and staying on the outermost edges of the map helps to prevent the player from being flanked. A Regenerator with an assault rifle is usually a good backup. Make a few kills then move to a different position.
 * Entering the lower levels through the "chute" is a good escape tactic. While being chased, strategically throwing grenades toward the exit of the chute can kill or wound any would-be pursuers.
 * In the lower levels, there are the many "spore pods" that explode, with some power, which can be used to the player's advantage.
 * Use the Ghost and find other players in the lower levels. As this is a tiny area that is hard to escape, it is easy to splatter opponents.
 * Climbing the trees in this map can provide good ambush points. If the player goes to the end branches and crouches with a suitable weapon they can sometimes and with practice, occasionally, score easy kills this way because opponents that are not extremely attentive will become disorientated thus easy targets.
 * In CTF, the player can pass the flag through the windows. If there is a teammate in the flag rooms and a teammate in the basement hallway, then a CTF match can be won really fast.
 * Holding the structure at the top with a team is extremely effective, as the player cannot be flanked, especially if their team has good aim and plenty of battle rifle ammo.
 * A team member can stand on top of the structure can spot enemies and call out their position so the whole team can use the high ground to kill them.
 * Get the shotgun, preferably the battle rifle and a Regenerator to stay on the open field, and the player can get some kills using CQB and long-range shots. Use this technique and repeat it again, however, go to the shotgun spawn first because it respawns very quickly.
 * The side lifts can be a handy escape from attackers. Sometimes the player can land in a tree and their pursuer will be looking for them on the ground.
 * A somewhat bold and insane tactic is to drive a Mongoose with a passenger wielding the Brute Shot. This is very effective for catching enemies’ off-guard, though the player is very vulnerable to battle rifle fire.
 * For FFA and Multi-Team matches, it is advisable to try to stay on the edges of the map.

Forge

 * Banshees can be spawned on this map, adding an element of surprise to the game.
 * If the player flies upwards to the top of a wall, they will die, but the Banshee will glide over the wall, and it will not respawn.

Trivia

 * Isolation is a map first referenced in the Halo 3 Beta code, and later appeared in a leaked photo of the list of Halo 3 maps.
 * Sentinels and Constructors can be seen flying above the map and can be shot at and destroyed, however, it is difficult. This is most easily done from the eastern side of the map with the help of scoped weapons. They will not, however, drop sentinel beams when destroyed; they simply explode in a blue flash.
 * The Flood Growth Pods on the walls of the cavern do not contain Flood Infection Forms like those in the Flood Infested High Charity. When popped, they scream or moan, rather than spew Infection Forms, but they do cause damage to anyone unfortunate enough to stand next to them when they are set off.
 * Over the course of a match Flood-like boils slowly grow on the grass hill, starting next to the sniper spawn and spreading outwards.
 * This is one of two maps that are Flood-based in Halo 3, the other being Cold Storage.
 * Elements on this map may have been inspired by the Halo 2 map, Backwash, another Flood-themed level.
 * Getting behind the Forerunner walls using Forge will lead to a full view of "The Ark" installation. Walking too far away from the wall will kill you.
 * Strangely, the planetoid is missing from the Ark's core.
 * The wall structures on this map are similar to those found in Valhalla, indicating that they may be connected. This similarity was alluded to in the eighth season of Red Vs. Blue, where Valhalla's large wall was smashed open, revealing Isolation on the other side.