The Warthog is the Primary UNSC Land Vehicle.
The Warthog has four variations that appear throughout the Halo trilogy: The M12 Light Reconnaissance Vehicle, M12A1 Light Anti-Armor Vehicle, M12G1 Light Anti-Armor Vehicle, and the M831 Troop Transport.
 M12 Light Reconnaissance Vehicle
The M12 Light Reconnaissance Vehicle, or M12LRV, has a driver seat, passenger seat, and a mounted M41 Light Anti-Aircraft Gun (or Turret, as it's commonly known) which can be used by a third person. This turret has a very high rate of fire, but is not the best choice for taking out armored vehicles. The M12 LRV has appeared in Halo: Combat Evolved, Halo 2, and Halo 3.
 M12A1 Light Anti-Armor Vehicle
This variant is not known my most console players. This is because this variant only appeared in the Mac and PC version of Halo: Combat Evolved. This Warthog is similar to the M12 LRV, except for a few key differences. The most noticeable difference is that this Warthog is bisected by a yellow stripe. The other difference is the 102mm SC-HE Rocket Turret mounted in place of the LAAG. This turret was very strong, but had a slow rate of fire and was not practical when taking out infantry. The M12A1 was commonly referred to as the "Rocket Hog".
 M12G1 Light Anti-Armor Vehicle
This was created to replace the M12A1 LAAV. The M12G1 LAAV is essentially the same vehicle as its predecessor, though without the yellow stripe and with a weakened, faster firing turret known as the M68 Gauss Cannon, which gives this new variant the nickname of "The Gauss Hog". This variant has appeared in Halo 2 and Halo 3.
 M831 Troop Transport
This variant was designed for transporting troops into combat. This Warthog can only carry two players, but has a rear seating area that can hold up to 5 NPC marines. This Warthog is only usable in campaign, and The Pit (if glitched).
 Primary Matchmaking Uses
The primary use of the Warthog in Slayer and King of the Hill gametypes is for combat. Both the LAAG and the LAAV cannons are ideal for killing players and destroying vehicles. In Assault and Capture the Flag, the Warthog is mainly used for transporting the bomb carrier or flag carrier. In Territories, it is used for suppression purposes.
Power Drainers will leave the Warthog motionless, making it very vulnerable to grenades and concentrated fire. The overcharged Plasma Pistol bolt has the same effect. Warthogs are extremely vulnerable to Trip Mines; a single well-placed mine has the potential to eliminate a full 'hog on contact. Naturally, Spartan Lasers and Missile Pods are also very effective.