(Required) 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 blocking the bridge to the collapsed overpass tunnel entrance.
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 leading to Ashton silo control station. When you come upon the marked men camp, head southeast towards the back of the camp. Tucked in with the rocks behind a truck is a warhead.
As you enter The Courier's Mile, 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.
The Divide - before the Cave of the Abaddon (5)Edit
As you exit the Ashton Silo on the Sunstone Tower rooftop, head to and peek 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 near the end of the building with the white old world flag on it.
(Required) Head northwest from the last warhead. You'll see another warhead wedged in-between the rocks.
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.
(Required) 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.