Fallout: New Vegas

These can be detonated during or after the story, as you can return at any time.

First, you obtain the Laser Detonator needed for this achievement as an objective of the quest, "The Job", and is a part of the main storyline.

Before Collapsed Overpass Tunnel Entrance - 5
- (Required) After retrieving the Laser Detonator in the Marked Men Camp, you have to blow up a warhead on a truck bed to leave the area. Can't miss it.
- Head back to the Hopeville Missile Silo Bunker exit. In front of the barracks that is across from the destitute gas station is another warhead.
- Following the path to the Collapsed Overpass Tunnel Entrance, it branches before entering the ruined city area. Among the bunkers off the right side of the right path is the warhead.
- In the very southeastern-most corner of the Marked Men-run ruined city you'll find another warhead in the center of the broken-down trucks and vehicles.
- Just before the Collapsed Overpass Tunnel Entrance is a warhead. Right in plain view.

Before Ashton Silo Control Station - 4
- After getting attacked by the first group of Marked Men past the Collapsed Overpass Tunnel and moving along, you'll start being fired upon by some more in the distance. Below their building and the path to The Crow's Nest is a warhead.
- The next warhead is found in the middle of the Ruined Highway Interchange area, surrounded by deathclaws.
- As you near the end of the highway, you'll come across a fork. Take the right path that heads downward toward a collapsed tunnel and a ruined vehicle. A warhead is near the "Smitty's Diner" sign, near the Junction 7 Rest Stop.
- After the last warhead, now take the left fork. When you come upon the Marked Men camp, head to the southeast. Tucked in with the rocks behind a truck is a warhead.

Courier's Mile (unlocked after setting off nuke at Ashton Silo Control Station as part of "The Launch" quest.) - 2
- As you enter the area, you'll see a fork. As you take the right one, you'll be able to see a warhead up ahead in the distance among the destroyed buildings behind the deathclaws.
- Back and along the left road, you'll come to a path and a clearing on your left full of Marked Men. Tucked away in the back with the ruined buildings is a warhead.

Before the Cave of the Abaddon - 5
- As you exit the Ashton Silo on the Sunstone Tower rooftop, head to and peak down over the western edge. Below, on the left-hand side of a large white "On Solid Ground!" billboard near a large, collapsed building you'll see a warhead.
- On the opposite side of the same billboard from the last warhead is another.
- (Required) From Sunstone Tower, head southwest. Tucked between the boulders is a warhead you have to detonate to continue along.
- Head around to the right from the last warhead. Up among the rubble on your right, you'll see only the tip of a buried warhead sticking out.
- (Required) Head northwest from the last warhead. You'll see another warhead wedged in-between the rocks.

Before Ulysses' Temple - 8
- After reaching the Boxwood Hotel Roof, head southeast. Behind a pipe gushing water you'll find the den of Rawr the Deathclaw. One is embedded in the ceiling.
- After defeating Rawr, another is used to leave the den
- (Required) Further along from the last two, at the base of a ruined building where some Marked Men are shooting from you'll spot a warhead.
- After passing under the building using the path created from the last warhead, look up and to the right. In the distance (above the entrance to the Waste Disposal Station area) you'll see a warhead sitting next to a Marked Man sniping at you.
- Head south from the toppled building. Around another gushing pipe, up among rocks, you'll find one.
- After detonating the previous warhead, a path leading up will be created. After climbing up, you'll be atop the toppled over building. Going around to the right will take you up to the entrance of the Wastewater Treatment Plant. The warhead is on the rocks to the left of this entrance.
- Look out southwest from this area and you'll see one atop the nearby building in the farthest corner.
- High up and to the right of the entrance to Ulysses' Temple.

Inside Ulysses' Temple (Note: all these can be detonated before starting the final dialogue. Also, there are large missiles scattered around. These aren't warheads and are ignored.) - 6
- Directly to your right as soon as you enter the large room is the first warhead. Make sure to back up.
- The next one is to the far left of the large room, along the wall next to a large missile.
- Further along the wall to the left opposite the last one is another warhead between two large missiles.
- Along the right wall is the next warhead, among some large missiles.
- Hidden in a recess behind the first large missile along the right wall is a rather sneaky warhead.
- The final warhead is alongside the right-hand side of the center walkway as you head toward Ulysses.

Here is a great video guide. I take no credit for this video, all credit goes to Xerxus. :) Hope this helps and happy nuke hunting!

If you prefer a visual guide but not a video, here is a map of The Divide with the warhead locations marked:


Access to Courier's Mile opens up after you complete the final quest. The entrance will be marked on your map, lower left corner near Hopeville.

(copy/paste the picture URL into your browser to enlarge it, if needed)

The above solution is a very nice guide for finding the warheads. If however you are like me and are just looking for a few scattered ones you missed without using a guide fear not. After you detonate a warhead, it leaves the area where it used to be in a permanent of flames. This is a good indicator for seeing which ones you've already detonated.

This is in my opinion a better video to follow, especially if you are like me and had only a few left to find. I take no credit for making the video just passing it along.