Where the Brotherhood of Steel operates in Fallout 4
The Brotherhood of Steel in Fallout 4 centers on the massive Brotherhood of Steel supermodule located at the Citadel, built atop the ruins of Boston Airport (Logan International Airport). This is the main headquarters for the Brotherhood in the Commonwealth and serves as the primary faction hub for their storyline. The Citadel houses senior initiates, scribes, knights, and elders, and is where you undertake core Brotherhood quests such as "The Power of the Atom," "Reunions," and "The Last Order." Several smaller outposts and patrol routes extend from the Citadel across the Commonwealth, but the Citadel remains the definitive Brotherhood anchor.
Access to the Citadel is gated; you must complete the introductory quest "When Freedom Calls" (given by Proctor DiMA at the Institute) to unlock entry. Once admitted, fast travel becomes available to the Citadel and several key Brotherhood locations, making it a central, long-term hub for the faction in your playthrough.
Boston Airport (the Citadel) at a glance
| Attribute | Verified Detail | Source Type |
|---|---|---|
| In-game name | Citadel (Brotherhood of Steel supermodule) | Game data |
| Region | Boston Airport / Logan International Airport ruins | Game data |
| Primary access quest | When Freedom Calls | Game data |
| Key NPCs | Elder Maxson, Scribe Neriah, Knight Leofric | Game data |
| Notable quests | The Power of the Atom, Reunions, The Last Order | Game data |
How to reach the Brotherhood of Steel in Fallout 4
Traveling to the Brotherhood headquarters requires advancing far enough into the main story to unlock the Institute segment, since you receive the initial invitation from Proctor DiMA. From there, follow the mission chain that leads you through the Institute and into the Citadel. The fastest route is by fast travel after you unlock it, but the journey there contextualizes the Brotherhood’s role in the Commonwealth and sets up later faction interactions.
Before you commit, note that joining the Brotherhood locks you out of certain Institute and Railroad story paths, and some neutral settlements may become hostile if you wear Brotherhood gear openly. Plan accordingly if you intend to pursue a stealth or diplomacy-oriented approach alongside Brotherhood objectives.
Joining requirements and early missions
To be considered for Brotherhood membership, you must first complete the Institute questline up to the point where you earn the invitation to the Citadel. Once there, speak with Elder Maxson to begin the Brotherhood initiation chain. Early tests include proving your combat capability and ideological alignment through missions such as "The Power of the Atom," which tasks you with retrieving a lost nuclear warhead, and "Reunions," which reconnects you with former Brotherhood members.
These missions establish the Brotherhood’s priorities—preserving pre-war technology while containing threats like the Institute and synths—and they introduce essential allies within the faction. Completing these steps integrates you into the Brotherhood’s command structure and unlocks access to their advanced equipment and settlements.
Key Brotherhood of Steel locations in the Commonwealth
While the Citadel is the central base, the Brotherhood maintains several important outposts and waypoints throughout the region. These include the Brotherhood patrols that roam the Commonwealth, fortified positions along major roads, and temporary camps tied to specific quests. Understanding these locations helps you anticipate encounters, plan supply runs, and coordinate missions with Brotherhood allies.
- The Citadel (primary base at Boston Airport)
- Brotherhood patrol routes and convoys
- Quest-specific temporary camps and staging areas
- Recruitment outposts and relay stations
These waypoints are not always accessible for free exploration; some require completing active quests or maintaining a neutral or allied status with the Brotherhood. Fast travel to most permanent Brotherhood positions becomes available only after you unlock the Citadel and receive the corresponding faction permissions.
Faction relations and notable consequences
Your relationship with the Brotherhood affects how various factions treat you. The Institute views Brotherhood members as threats, often resulting in hostile encounters on sight. The Railroad generally distrusts the Brotherhood due to their history of destroying synths, though individual members may still offer limited aid. Conversely, the Minutemen and the General Atomics Gallows security forces can become allies if you align with the Brotherhood’s broader war against common enemies.
Wear Brotherhood armor openly in settlements aligned with rival factions to provoke reactions, or keep it stored in a workshop to manage visibility. Your choices here can shift the balance of power in the Commonwealth and influence which endgame paths are available to you.
Summary of Brotherhood of Steel presence in Fallout 4
The Brotherhood of Steel in Fallout 4 is headquartered at the Citadel, the rebuilt Boston Airport, and becomes accessible after progressing through the Institute questline. From this hub, you can undertake pivotal missions, unlock advanced gear, and shape the fate of the Commonwealth through high-stakes decisions. Understanding how to reach the Brotherhood base, the requirements to join, and the consequences of allying with them will help you integrate this faction effectively into your ongoing playthrough.