TL;DR

There are 42 skulls in Halo Campaign Evolved — 39 are hidden across 13 missions (3 per mission), and 3 unlock automatically via Campaign Remix.
Every skull works as a gameplay modifier you can toggle on or off before starting a mission.
Skulls can be collected on any difficulty — most do not require Heroic or Legendary (the Catch skull in Keyes is the exception).
None are permanently missable — you can replay any mission or use chapter select at any time.
Collecting all 39 hidden skulls unlocks the Headhunter achievement. Getting all skulls and terminals unlocks Collector’s Addition.
The Acrophobia skull (The Silent Cartographer) lets you fly — grab it early to make high-up skulls much easier.
Skulls glow faintly and emit a whispering or hissing sound as you get close.

Halo Campaign Evolved All Skull Locations & Effects is one of the most searched topics in the game. Every single mission — including all three bonus prequel missions — has three skulls hidden somewhere inside it. Some are easy to spot once you know where to look. Others need enemy clears, grenade jumps, timed runs, or multi-step triggers before they even spawn.

This guide covers every skull in every mission, in order, with its location and what it does. Whether you are on PC via Steam, Xbox, or PlayStation, this guide covers all platforms.

Table of Contents

How Skulls Work in Halo Campaign Evolved

Skulls are the main collectibles in Halo Campaign Evolved alongside terminals. Each skull you find unlocks a gameplay modifier. You can activate these modifiers from the mission select screen before starting or replaying a level. Some skulls make the game harder. Others — like Bandana and Acrophobia — actually make things easier, and grabbing them first can help you reach other skulls faster.

When you are near a skull, it will emit a faint hissing or whispering sound that gets louder as you get close. They look exactly like a human skull and they glow slightly. Keep your ears open whenever you are off the critical path in any mission.

One important tip before you start skull hunting: grab the Acrophobia skull in The Silent Cartographer first. It lets you fly by double jumping, and it turns a lot of otherwise hard-to-reach skull locations into simple floats. For a broader overview of the game before diving in, see the Halo Campaign Evolved beginner’s guide and the all missions list.

The Pillar of Autumn Skull Locations

Skull 1: Speed Limit

As soon as you step out of your cryo pod at the start of the mission, head to the back wall with the UNSC symbol on it. Jump onto the two containers on the walkway nearby. The Speed Limit skull is sitting on the walkway to the left of the containers.

Effect: Sprint is disabled.

Skull 2: Magnified

Follow the objective markers toward Captain Keyes on the Bridge. You will pass through the armory — look for the room with the wall labeled B02L. Inside, jump up the fourth set of gun racks in the center of the room to find the skull on top.

Effect: Assault Rifles have 60-round magazines instead of the standard count.

Skull 3: Perspective

After you meet Captain Keyes on the Bridge, leave the area until you can draw your pistol. Once your pistol is out, head back to the Bridge and walk to the far end of the room where two pilots are standing. Drop down between them. The skull is to the left of the ladder down there.

Effect: Enables a third-person camera mode. See our Halo Campaign Evolved third-person guide for more on this.

Halo Skull Locations

Skull 1: Give & Take

When you cross the bridge with your Warthog and reach the surface, drive up the hill and turn right. Before following the mission objective, turn left and follow the river stream. The Give & Take skull is sitting on a rock to your left along the riverbank.

Effect: Firing your weapons drains your shields, but dealing damage to enemies recharges them.

Skull 2: Floor is Lava

Drive the Warthog to the right-side lifeboat crash site by the rock cliffs. Get out and go to the back of the area. Face the rock structure there and look down. The Floor is Lava skull is visible from this spot below you.

Effect: Touching the ground deals damage to you. You need to keep off the floor as much as possible.

Skull 3: Grunt Funeral

Head to the far-left lifeboat crash site, near the cliff and the central building. Instead of heading underground as the objective asks, climb the central tower using the diagonal ramps on its exterior. Once at the top, you need to perform a grenade jump — throw a grenade at the floor, then jump timed with the explosion to boost yourself higher. The Grunt Funeral skull is up there.

Effect: Grunts explode in a blaze of plasma when they die.

For the complete collectible rundown on this level, see the Halo mission skulls & terminal guide.

Truth and Reconciliation Skull Locations

Skull 1: Iron

After killing the Hunters at the grav lift section, head toward the cliff edge and look down. There is a rock below that has the Iron skull sitting on it. You need to drop down to reach it. Getting back up without dying is not easy, so be prepared to respawn after grabbing it.

Effect: In co-op, dying resets to the last checkpoint. In solo, dying resets the entire level.

Skull 2: Endurance Spec

When you are tasked with finding the ship’s brig, you will enter a large two-floor room. Head upstairs to the balcony and climb up the structure on the left. From there, run and jump across three pillars — the skull is sitting on top of the last pillar. This jump takes a few attempts and requires you to sprint without stopping between platforms.

Effect: UNSC vehicles cannot take damage.

Skull 3: Foreign

While clearing Covenant reinforcements in the ship’s brig area, hang around near where you spawned into the section. There is a locked door behind you. Enemies will open it as they pour out. Slip in through the door before it closes again. Follow the hallways inside to find the skull at the end.

Effect: You cannot pick up or use weapons from the Covenant faction.

Full details on this level are in the Truth and Reconciliation skulls & terminal guide.

The Silent Cartographer Skull Locations

Skull 1: Bandana

Once you have your Warthog, you will be directed to find the Silent Cartographer building. Instead of going into the marked building, go around it to the right. You will find a cave. The Bandana skull is in the center of the cave.

Effect: Infinite ammo and infinite grenades. One of the most useful skulls in the game for collectible hunting.

Skull 2: Acrophobia

Your Warthog path will eventually take you to a central building with two Hunters guarding it. Kill both Hunters. After they are down, climb the diagonal slope on the side of the central building. The Acrophobia skull is sitting at the very top.

Effect: Double jumping allows you to fly. This is the single most useful skull for reaching other skull locations across the entire game. Grab this one first if possible. See our Halo Campaign Evolved how to fly guide for more on using it.

Skull 3: Hip Fire

When you return to the Silent Cartographer building to find the cartographer (the door will be unlocked now), head down the stairs into the large room with two Hunters. Deal with them. At the back of the room is a staircase with a blue railing. Look down into the hole below the staircase — the Hip Fire skull is sitting on a platform to the right inside the hole.

Effect: Weapon zoom and aiming down sights is disabled. You can only fire from the hip.

See the full The Silent Cartographer skulls & terminal guide for step-by-step detail.

Assault on the Control Room Skull Locations

Skull 1: IWHBYD

Once you get the Scorpion Tank, drive it through the substructure until you reach a bridge. Cross the bridge and immediately turn left toward the ice cliff on the far side. Leave the tank, climb on top of it, and from there run and jump onto the small snowy rock sticking out from the cliff. The IWHBYD skull is on that rock.

Effect: Unlocks secret dialogue lines from characters throughout the game.

Skull 2: Angry

Eventually you will reach a cave too narrow for the Scorpion Tank. Leave it and enter the cave on foot. On the other side is an open area with Ghost vehicles and three structures in the center. Climb the side of the back structure. The Angry skull is on top of it.

Effect: Enemies fire their weapons faster and far more aggressively.

Skull 3: Cowbell

Deep into the mission, when your next objective becomes heading for Halo’s Control Room, you will spot Banshees in the area. Ignore them for now. Look for the central structure in this section. In the middle of its railing, drop down from the railing to land on the rock below. The Cowbell skull is there.

Effect: The physical mass of objects is reduced, making everything fly much farther when hit or exploded.

See the Assault on the Control Room skulls & terminal guide for the full walkthrough.

343 Guilty Spark Skull Locations

Skull 1: Fog

Right at the start of the mission, you will come across a Covenant dropship that has crashed into a tree. Face the ship and then turn left. Walk up the hill on your left and keep your eyes to the right as you go. When you see two smaller trees close together, climb between them. The Fog skull is sitting on a ledge overlooking the cliff.

Effect: The motion tracker on your HUD is disabled.

Skull 2: That’s Just… Wrong

As you search for Captain Keyes deeper in the mission, you will move through a room full of dead Covenant bodies. Keep going through. In the next section, a human Marine will start shooting at you. Kill the Marine. When he drops, you can loot the That’s Just… Wrong skull from his body.

Effect: Enemies have sharper awareness and react to you much faster.

Skull 3: They Come Back

At the very end of the mission, your objective becomes eliminating the Flood while waiting for evac. There is a large building in this area. Walk around the outside of the building until you find a way into a dark forest section behind it. Look for a glowing green plant. Follow it around and you will find a toppled tree you can walk across like a bridge. The They Come Back skull is on the ground at the end of it.

Effect: Flood combatants become stronger when they reanimate instead of dying outright.

For the full breakdown with the terminal, see the 343 Guilty Spark skulls & terminal guide.

The Library Skull Locations

Skull 1: Tilt

When you take the elevator into the lower chambers, you enter a large corridor swarming with Flood. Guilty Spark’s drones will be with you too. In this large room, hug the back wall and look to your left. There is a ramp-like pillar you can climb. The Tilt skull is at the top of it.

Effect: All damage multipliers — both positive and negative — are enhanced. Weaknesses hurt more, resistances protect more.

Skull 2: Pop

After going down in the elevator, you hit the checkpoint called “Wait, It Gets Worse.” Head down one of the corridors (left or right both lead to the same place) until you reach a locked door. Turn around and look for a ramp-like pillar nearby. Climb it, then jump onto the cylinder at the top, and jump from there onto the platform in the center. The Pop skull is on that platform.

Effect: Shooting Flood in their weak points causes them to explode violently.

Skull 3: Famine

Much later in the mission, take the elevator to the final chamber. You will hit the checkpoint “Fourth Floor: Tools.” In this room there are three paths: left, right, and a ramp going down in the center. Take the ramp down and immediately turn left. The Famine skull is on the floor right there.

Effect: Weapons dropped by enemies contain only half their normal ammo.

For the full level guide, see The Library skulls & terminal guide.

Two Betrayals Skull Locations

Skull 1: Tough Luck

Once you exit the building at the start of the mission, head down to grab a Banshee as your objective asks. But instead of following the mission marker, fly the Banshee directly above the building you just came out of. Above the central pillar on the roof of that building is the Tough Luck skull. Land the Banshee on top and grab it before continuing.

Effect: Enemies always go berserk, dodge gunfire, and never fall back or retreat.

Skull 2: Black Eye

When your objective sends you through the adjacent canyon toward the second pulse generator, you navigate through a structure and come back outside. You will see three large ramps just in front of a Ghost vehicle. Head behind the ramps to the back-right corner where Flood spores are scattered. The Black Eye skull is in that corner.

Effect: Your shields only recharge when you land melee attacks on enemies.

Skull 3: Mythic

This one takes effort. From the Black Eye skull location, move through the canyon until you see a Banshee on the left and Hunters fighting Flood on the right. Take the Banshee on the left and fly it up to the landing platform above. Interact with the terminal there to open a door. Fly up into the new area through that door. Inside is a room with Grunts using Fuel Rod guns and Elites. Clear them all, then use the door panel to unlock another door. Follow the corridor to a room full of Flood. Kill them all. The Mythic skull spawns in the center of the room after the last enemy dies.

Effect: All enemies have significantly more health.

For the complete guide, see Two Betrayals skulls & terminal guide.

Keyes Skull Locations

Skull 1: Catch

Important: This skull requires you to play on Heroic or Legendary difficulty. You also cannot have other skulls active. From the start of the mission, you need to reach the grav lift within 5 minutes — the timer resets if you restart from a checkpoint. Follow the path quickly, kill the Covenant at the grav lift, and spam the interact button to float up. The Catch skull will be waiting on the ground when you land at the top.

Effect: Enemies throw and drop grenades far more frequently.

Skull 2: Blind

Your objective will send you toward the shuttle bay. You will pass through a large hangar area with Ghost and Wraith vehicles. Drop down into the hangar and look for an open door in the back corner. The path through is blocked by a Covenant Wraith, but you can crouch and slip underneath the Wraith to get through. The Blind skull is at the end of this crouched corridor by a locked door.

Effect: Your entire HUD is disabled and weapons no longer appear on screen.

Skull 3: Pinata

After the cutscene where you find Captain Keyes, immediately turn back around to face him. Start meleeing him. Keep hitting him until the Pinata skull literally pops out of him and falls to the ground. Pick it up.

Effect: Punching enemies causes them to drop grenades when hit.

See the Keyes skulls & terminal guide for the full breakdown including the terminal.

The Maw Skull Locations

Skull 1: Stowed Reload

After the bridge cutscene with Cortana and Guilty Spark, your new objective becomes reaching the cryo storage facility. Follow the main objective until you enter a room with four cryo pods where Sentinels and Flood are fighting each other. Look to the back-left corner of this room. On the destroyed catwalk above that corner, the Stowed Reload skull is sitting up there. Jump up to reach it.

Effect: When you switch to a secondary weapon, your active weapon automatically reloads while holstered.

Skull 2: Boom

Navigate through the hallways until you hit the checkpoint called “Light Fuse, Run Away.” Head right and go up the ramp. Then go left. You will find an unlocked door in the right wall — enter it to reach Floor 2. Continue on the linear path left to reach Floor 3. There is a walkway here with two main objective consoles. Ignore them. Jump over the gap ahead to reach an open doorway, then drop down a small ledge into the gap below it. The Boom skull is in that gap.

Effect: Explosion radius is doubled for all explosions.

Skull 3: Thunderstorm

During the Warthog escape sequence, drive down into the tunnel and watch to the right for an open door. Drive through it. Then continue right where a second door opens. Leave the Warthog and walk through that second door. The Thunderstorm skull is sitting in the middle of the room to the right.

Effect: Most enemies are upgraded to a higher rank, making standard enemies more dangerous.

For the full collectible route, see the The Maw skulls & terminal guide.

Boarding Action Skull Locations (Bonus Mission 1)

Boarding Action is the first prequel bonus mission. For the full detailed guide to all three skulls and the terminal, see the Boarding Action skulls & terminal locations guide.

Skull 1: Malfunction

After killing two Hunters, ignore the grav lift. Head down the right-side path, take the stairs, and pass the Covenant dropship. Enter the door on the right side of the ship, pass the mountable turret, and continue to the bridge. The skull is on the floor of the bridge.

Effect: Each time you respawn, a random HUD element disappears permanently for that life.

Skull 2: Johnny Ammo Seed

Fight through to the Covenant training grounds — four tree pillars, a sand pit, weapons on the floor. Clear the enemies. Head up the stairs and take the left door at the top. Kill the Elite ambush inside. The skull is on a ledge to the right of the room.

Effect: Reloading a weapon mid-magazine wastes the remaining bullets in the current clip.

Skull 3: Leadhead

Before taking the second grav lift upward, look for the door in the back-left corner of the grav lift room. Go through it and follow the corridor to the end. The skull is there.

Effect: Headshots deal no bonus damage and cannot score instant kills.

The Most Dangerous Game Skull Locations (Bonus Mission 2)

The Most Dangerous Game is the second bonus prequel mission. For the full detailed walkthrough of all three skulls and the terminal, see the The Most Dangerous Game skulls & terminal locations guide.

Skull 1: Temperamental

This is the most complex skull in the game. You need to break the shields of a golden High-Value Target Elite across three separate encounters. The HVT cannot be killed — only its shields can be stripped. All three encounters must be completed in one run. After the final shield break, clear all enemies in the area and the skull spawns on the central purple structure.

Encounter 1: After rescuing Williams, enter the purple tree forest. The HVT is on the ledge to the right.
Encounter 2: At the large bridge. The HVT is on the far side by the locked door, to the left of a Wraith.
Encounter 3: After exiting the prison block back outside, look up and left. The HVT is on a rooftop.

Effect: Allies immediately turn hostile toward you if you shoot and kill a UNSC soldier.

Skull 2: Recession

At the large bridge (same area as HVT Encounter 2), turn around to face the direction you came from. There is a locked purple door with a pillar on each side. Each pillar has an explosive box on top. Shoot both boxes to blow them up. The door opens. Walk in and grab the skull.

Effect: Every shot fired costs two bullets instead of one, halving your effective ammo.

Skull 3: Ghost

After the Banshee attack and crossing the grav bridge, go through the gate into the final outdoor enemy area. Immediately turn around. Look up at the purple pillar to the right of the gate you just walked through. The Ghost skull is on top of it. Reach it by climbing the wall indents near the large tree on the left, then jumping across to the pillar.

Effect: Enemies do not flinch or stagger when you shoot them.

Heavy Burden Skull Locations (Bonus Mission 3)

Skull 1: Eye Patch

Progress through the mission until you reach a bridge. Instead of crossing it, enter the room on the left side of the bridge. This room gives you access to a catwalk above. Follow the catwalk all the way to its end. The Eye Patch skull is in the right corner at the far end.

Effect: Auto-aim is disabled completely. All aiming is manual.

Skull 2: Grunt Birthday Party

Later in the mission, you will reach a room with two doorways — one on the left and one on the right — and a rock structure between them. The Grunt Birthday Party skull is on top of that rock pillar. To get there, go through the left doorway and drop to the platform below. There is a purple fire pit facing the rock. Jump onto the fire pit, then jump across to the rock pillar. Jump up and hold interact to grab the skull.

Effect: Grunt headshots cause them to explode in a shower of confetti and celebration.

Skull 3: Efficient

This skull is found toward the end of the mission on the moving platform section. Board the moving platform and ride it through the rooms. When the power shuts down and you turn it back on, jump back on the platform and ride it through the first room with the bridge. In the room that follows, jump off to the platform on the left and sprint hard to the back-right corner. The Efficient skull is in that corner. Warning: you are out of bounds here and will die after 10 seconds if you do not make it back to the moving platform in time.

Effect: Enemies killed while you are at full health drop more ammo than normal.

The 3 Automatic Skulls (Campaign Remix)

Three skulls in Halo Campaign Evolved do not need to be physically found. They unlock automatically once you access the Campaign Remix mode, which becomes available after finding your first few hidden skulls. These three are:

Adaptation: Enemy types are randomized across the mission.
Reload: Weapon placements and spawns across the level are randomized.
Armistice: All enemy factions fight alongside each other rather than against one another.

These three count toward the 42 skull total but are not required to be hunted down manually.

Complete Skull List: All 42 Skulls & Effects

Skull	Mission	Effect
Speed Limit	The Pillar of Autumn	Disables sprint
Magnified	The Pillar of Autumn	Assault Rifles have 60-round magazines
Perspective	The Pillar of Autumn	Enables third-person camera mode
Give & Take	Halo	Firing drains shields; dealing damage recharges them
Floor is Lava	Halo	Touching the ground deals damage
Grunt Funeral	Halo	Grunts explode in plasma when killed
Iron	Truth and Reconciliation	Death resets level (solo) or last checkpoint (co-op)
Endurance Spec	Truth and Reconciliation	UNSC vehicles cannot be damaged
Foreign	Truth and Reconciliation	Cannot pick up or use Covenant weapons
Bandana	The Silent Cartographer	Infinite ammo and grenades
Acrophobia	The Silent Cartographer	Double jump to fly
Hip Fire	The Silent Cartographer	Weapon zoom and aiming disabled
IWHBYD	Assault on the Control Room	Unlocks secret character dialogue
Angry	Assault on the Control Room	Enemies fire faster and more aggressively
Cowbell	Assault on the Control Room	Objects have reduced mass and fly much farther
Fog	343 Guilty Spark	Motion tracker disabled
That’s Just… Wrong	343 Guilty Spark	Enemies have sharper awareness and faster reaction
They Come Back	343 Guilty Spark	Reanimated Flood are stronger than before
Tilt	The Library	All damage multipliers (positive and negative) enhanced
Pop	The Library	Shooting Flood weak points causes explosions
Famine	The Library	Enemy weapon drops contain half ammo
Tough Luck	Two Betrayals	Enemies berserk, dodge fire, never retreat
Black Eye	Two Betrayals	Shields only recharge via melee attacks
Mythic	Two Betrayals	All enemies have more health
Catch	Keyes	Enemies throw and drop more grenades (Heroic/Legendary only)
Blind	Keyes	HUD hidden and weapons invisible on screen
Pinata	Keyes	Punching enemies causes them to drop grenades
Stowed Reload	The Maw	Weapons reload automatically when holstered
Boom	The Maw	Explosion radius doubled
Thunderstorm	The Maw	Most enemies upgraded to a higher rank
Malfunction	Boarding Action	Random HUD element disappears on each respawn
Johnny Ammo Seed	Boarding Action	Reloading wastes remaining magazine ammo
Leadhead	Boarding Action	Headshots deal no bonus damage or instant kills
Temperamental	The Most Dangerous Game	Allies turn hostile if you kill a UNSC soldier
Recession	The Most Dangerous Game	Every shot costs two bullets
Ghost	The Most Dangerous Game	Enemies do not flinch when shot
Eye Patch	Heavy Burden	Auto-aim disabled
Grunt Birthday Party	Heavy Burden	Grunt headshots cause confetti explosions
Efficient	Heavy Burden	Full-health kills drop more ammo
Adaptation	Campaign Remix (auto-unlock)	Enemy types are randomized
Reload	Campaign Remix (auto-unlock)	Weapon placements and spawns randomized
Armistice	Campaign Remix (auto-unlock)	All enemy factions fight together

Tips for Collecting All Skulls Efficiently

With 39 skulls spread across 13 missions, doing this without a plan can take a long time. Here are some practical tips to get through the hunt faster.

Get Acrophobia first. It is in The Silent Cartographer and lets you fly by double jumping. This single skull removes most of the difficulty from climbing to high ledges across the whole game.
Grab Bandana early too. Infinite ammo and grenades mean you can focus on finding collectibles instead of managing resources. Both Bandana and Acrophobia are in the same mission.
Use chapter select freely. You can jump to any section of any mission. Picking up a skull saves immediately — you can quit out right after and it counts.
Do the Catch skull separately on Heroic or Legendary. This is the only skull with a difficulty requirement and a time limit. Plan a dedicated run for it rather than mixing it with other skulls on Easy.
Listen for the audio cue. That faint hissing sound is your best friend when you are in the general area but cannot see the skull yet. Stop, be quiet, and follow the sound.
Play co-op for tricky encounters. Missions like The Most Dangerous Game are far easier with a second player. Find out how many players co-op supports in Halo Campaign Evolved.

Mission-by-Mission Skull & Terminal Guides

If you want the full detail on a specific mission — including terminal locations — use these guides. Each covers all three skulls and the terminal for that level.

You may also find these other guides useful as you work through the game: