The check point broadcasts an old world military beacon emergency frequency RJ1138, calling all South Boston Army soldiers to its coordinates.
As of 2287, the checkpoint has fallen under Gunners control, with an unnamed Gunner commander in charge of it.
It is located directly west of the Castle and past the bridge just outside of the South Boston area. It consists of two structures, the main building (2 Gunners) and a trailer (1 Gunner) along with various car wrecks and a sentry bot (who has mysteriously wandered off to the Red Rocket nearby). The main building has a Master safe with plenty of ammo, various loot chests and behind the structure is a full suit of leveled power armor behind an Expert terminal.
- Fat Man - Found inside the trailer.
- Leveled power armor - Found inside the locked cage (Expert hacking) just outside the checkpoint building.
- Mini nuke - 1 found inside the locked cage behind the power armor.
- Guns and Bullets issue #7 - On a desk within the checkpoint building.
- 2 fusion cores - One near the elevator to the highway, one pre-installed in the power armor suit.
- Sleepwalker's note - It is found on top of an overpass inside of a camper in an unmarked location accessible by a lift east of South Boston military checkpoint.
- Learning Curve - This is one of the locations the Sole Survivor can escort a scribe of the Brotherhood to.
- Quartermastery - Recover tech for Scribe Haylen.
- The power armor frame here yields a full suit of leveled power armor that maxes out at X-01 Mk I at level 28, quite in contrast to other full X-01 sets that reach a maximum tier of Mk III at level 47.
- The items (including the Fat Man) respawn faster than the Gunners do.
- Several companions have quotes when entering the checkpoint area:
- Nick states that the repeating message was there "as long as [he] knows," and that "This must be the reason everyone's crazy inside."
- Hancock states with a level of stress in his voice, that "There must be a way to turn it off!"
- Cait and Preston Garvey similarly mention a need to turn off the transmitter.
- Piper sarcastically says "Ugh! Yes! We hear you." as the transmitter repeats.
The South Boston military checkpoint only appears in Fallout 4.