Fallout 4 obviously had to shrink a lot of places for the sake of being a game and making everything fit within a playable area that would be accessible and interesting to the gamer. Which is cool, I understand that. I wouldn’t want Boston and its surrounding countryside to be just as big as it is irl because… getting around places would be miserable. And my computer would probably die. So this is absolutely not a bash on the very smart decision to shrink Boston xD

When I’m writing fanfiction, though? I want Diamond City to be a city. I want the Prydwen to house an army. So I’ve done a little digging into what sorts of populations might be (more or less) realistic in a world where Fallout is purely a story and not also a BAMF videogame.

This is by no means a complete or painstakingly foolproof set of data lol But IT IS something I’ve been rolling around for a little while for the sake of my own fanfics SO I thought I would share! 

Diamond City - 3,000 | Goodneighbor - 800 | Bunker Hill - 400+ | Settlements 20-200 | The Castle - 100-400 |  Prydwen/Airport - 2,000 | Institute - 2,500 (400 Gen 3s)

My reasoning for each number and helpful pictures:

Diamond City - pop. 3,000

The Great Green Jewel! Fenway Park has a capacity of 37,731. Obviously as a living space that would need to be cut significantly to make room for houses, collapsed sections, shops, the water supply and crops, etc. Then add a little back because the farmers, for example, just sleep piled together under little to no shelter outside, houses can be stacked, plus the inner rooms of the stadium and the field itself are free real estate. 

(Source: Billie Weiss, larger view here) | Tentatively cutting the capacity to 1/10th, that’s about 4,000 people. If they can only use half the stadium, that’s still 2,000. Using (this discussion) as a basis, Diamond City would need 10 or so smaller settlements nearby to support their population, which would be feasible (even accounting for, well, it being the apocalypse, and settlements not always being permanent fixtures.) 3,000 sounded like a lot to me initially, but compared to that massive stadium above, it’s actually pretty reasonable looking! There’s supposed to be about 3k people in this photo:

(Source: Sports Illustrated, larger view here) | Diamond City is a trading hub, widely regarded as the safest place to be in the Commonwealth. People settle down here, raise families. I wouldn’t want to make it bigger (this is the apocalypse, after all) but a population that hovers around 3k would make sense, relatively invulnerable but not untouchable, far outstripping the other settlements around in size.

Goodneighbor - 800

Using townhouse neighborhoods as a basis, it would be pretty easy to pack 600 people into a single street and still have room leftover. Piper makes a comment about Goodneighbor parades if you talk to her in an area occupied by super mutants, so assuming the town has a long enough street(s) to run a parade, it wouldn’t be too hard to fit this sort of population in. Unlike Diamond City, though, people don’t generally think of Goodneighbor as the place to settle down and build a family. It’s occupied by mobs and drifters and general outcasts, so while it’s certainly a hub, it doesn’t have the same security and roots DC can claim. It’s still sizeable at 800.

Bunker Hill - 400+

Being primarily a trading hub, I don’t imagine Bunker Hill having much in the way of a permanent population. Plus, they don’t have that much space compared to the other places here, especially if they are having to accommodate caravans with pack brahmin and all their trade stalls. During peak trading season, Bunker Hill might swell far beyond it’s capacity, overflowing the inn(s) and turning into general chaos. In poorer times it might shrink as traders hit the road looking for greener pasture. 400 sets it solidly as a settlement on the rise, but it’s still vulnerable and not quite ready to challenge DC for trade dominance. | (From Google Maps, cars on the road for a sense of scale)

Settlements 20-200

Even excluding small family farms who would probably only be able to feed themselves and not contribute greatly to the Commonwealth’s economy or militaries, settlements would still probably not exceed 100 people in most cases. (For example, twenty families of three would give a settlement a population of 60.) Also, I figure there are many more of these little villages scattered around than just those featured in-game!

The Castle - 100-400

During the 1770s, Fort Independence housed the 64th Regiment, which was a single battalion of about 790 troops. But that was for a Boston with a population of about 13,000 (another 3,000 British troops were camped inside the city itself + 400 marines on ships in the harbor.) Rebuilding the Minutemen would take a lot of time, and most volunteer soldiers wouldn’t live at the Castle itself permanently - they have farms and families to protect. A number would need to be stationed to protect it, refugees might funnel in when settlements are overwhelmed, and most training would probably take place in the Castle, too. So depending on the season and relative safety of the countryside at any given time, a fluctuating mark of 100-400 seems appropriate! | Car near the bottom gives a sense of the Castle’s real size! (Source: Steve Dunwell)

The Prydwen/Airport - 2,000

Admittedly this one is a bit harder to justify. The Hindenburg, which I’m using for scale, only housed about 90 people. At first I thought to just add in some additional carriers in escort, but the lore gets a bit squiffy there because any story ending that involves destroying the BoS only accounts for their bigass mothership. So I’ll chalk that up to hubris and the Brotherhood assuming their firepower would be sufficient. The Prydwen would not be a luxury vessel, unlike the Hindenburg, so space would likely be much more efficiently utilized. And once they arrive in the Commonwealth, they won’t all be crammed on the ship. If it’s functioning mostly as a hub and transport, the BoS might get by stuffing the Prydwen like a turkey for a spell. 2k would be a significant force, especially with their equipment, enabling them to feasibly challenge the Institute. It would also have them rivaling Diamond City in terms of need for food and water, explaining the strain their presence puts on nearby settlements. | (Image and Hindenburg facts here!)

The Institute - 2,500 (400 Gen 3s)

Thiiiis one I’m the least certain about. The Institute needed to maintain a viable genetic diversity to exist mostly isolated for two hundred years, which means they had to have started with at least 98 people. (source) (alternatively, MVP calculations tend to sit in the thousands.) Depending on the size and stocking of the shelter the survivors holed up in, many more could have been part of this initial Eden.

Population would have to be strictly regulated due to limited space, but must be significant compared to surface factions to justify the Insititute’s reach. With synth labor that doesn’t need food/sleep, tunnel expansion could happen quickly. But power, building materials, and food would be limiting factors.

Slave-owning states in 1860 US tended to have populations made up of about 40% slaves. (source) Something a little lower than this for the Gen 3s population size would make sense considering their roles inside the Institute itself are more limited. Gen 3 population would also need to be limited to a realistic number for the Railroad to bust out if you choose the Railroad ending - high enough to justify the invasion, low enough to not totally overwhelm the organization if they escape.

Gen 1 and 2 synths being robotic and lacking the need for food/sleep would make keeping them around in large quantities much easier than Gen 3s. There could be several, several hundred, thereby placing the Institute well over any surface settlements in terms of size, but since these synths don’t have the same needs as organic life I’ll leave them out of this estimate. There are also an unknown number of Gen 3s infiltrating the Commonwealth as spies, but I’d leave them out of the tally too since they wouldn’t impact the Institute’s immediate need for food and space.

SO with all that in mind! I’d put the Institute at 2500, 400 of which are Gen 3 synths. Human population only slightly bigger than the Brotherhood’s invading force, but with Gen 1 and 2 synth bodyguards, a formidable foe. Still smaller than Diamond City which has the benefit of open doors to the outside world.

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A lot of these places could arguably sustain higher populations, but I also wanted to preserve the general lonely, end of the world feeling by leaving some empty space. Plus, the Commonwealth is dangerous! People get eaten and stuff!!

It’s possible I’ve missed out some history facts or in-game lore offering more specific info about these populations, so feel free to reblog/reply/ask/dm me if you have something to add (nicely pls, these are only headcanons and this is all in good fun!)

Obviously there’s no one right answer in the world of fanfic, what works for one person’s stories might not work someone else’s, so this definitely not a definitive guide! But it’s interesting to discuss c:

This is a good post! The only thing I would note is that it would be more accurate to compare the Prydwen to the USS Akron, a real military airship and flying aircraft carrier flown by the United States Navy in the early 30′s. It was roughly the same size as the Hindenburg, however its complement was only half of that of the passenger craft’s capacity (60 to the Hindenburg’s 120 passengers and crew). This is because, although space may have been used more ergonomically, they also had more to carry (including heavy machinery) and because overcrowding inhibits crew functionality. 

The same would be true for the Prydwen, which also acts as an aircraft carrier for vertibirds. Perhaps it’s actually larger than it appears in the game? But there’s still a limit to how large it could be while still remaining airborne, the amount of fuel it would have to use and carry, and the materials that would have been needed build it. Then there’re the supplies for the crew itself and their storage, not just weapons but the food and medical equipment (though that’s assuaged by the commandeering we know they do once they’re in the Commonwealth, they had to have had at least enough to get there in the first place. I don’t think they would have planned on making stops along the way to pick up more). The more larger the complement, the more they would have needed. They also brought along Liberty Prime’s components, and who knows how heavy those were.

Plus, this is an offshoot of a larger military force. It’s hard to say how large the entirety of the BoS would be by the time of Fallout 4. How large can a military in a post-apocalyptic setting be and still be manageable to its command? How many soldiers could they afford to send to the Commonwealth? I really couldn’t say, but it’s something to think about.

It would have been filled to maximum capacity for its transit from the Citadel to the Boston Airport, which I would cap at maybe 300-500 (assuming it’s a comparable size to the Akron or slightly larger). Even that may be pushing it though. They’d be packed like sardines for the duration of the trip. Things would be easier once they made it to their destination, when the nonessential crew and complement could relocate to the ground. They’d still have to support their troops. Again, there’s the commandeering, but how much of an impact that has on the locals outside of initial confrontations isn’t shown in-game, so it’s hard to estimate how much they take relative to settlement population sizes.

I think this is a tiddies out kind of look…

Steal his look

YES

Okay but that’s just a bespoke Vault Suit.