Settlement details for Covenant in Fallout 4. For information about the area, check out the page [Covenant] (Area)](/fallout-4/guide/walkthrough/lexington/covenant).
This page contains SPOILERS for the quest Human Error.
After completing the quest Human Error you can claim Covenant as a settlement, although the details vary considerably depending on how you completed said quest.
If you declined Dr. Chamber’s deal and freed Amelia Stockton, the settlers at Covenant will be hostile towards you. You’ll have to kill them all before you can claim the settlement, after which it’ll function more or less like a normal settlement.
If you accepted Dr. Chamber’s deal, return to Covenant afterwards and talk to Jacob Orden, who will ally with you, allowing you to claim the Workshop and develop the settlement. The original inhabitants will remain in Covenant, starting you off with nine settlers. This might sound like a good thing, but you cannot give any of these original inhabitants (even the generic settlers) any orders. Penny Fitzgerald and Doctor Patricia will continue functioning as merchants, two of the generic settlers along with Ted Huntley are farmers, while all the rest are just dead weight, contributing to your settler count, requiring resources, and contributing nothing.
Even without the original settlers serving as liabilities, Covenant has many serious limitations that make it a less than ideal settlement. First, the turrets outside do not actually contribute to your Defense rating, they cannot be moved, and they cannot be scrapped. They may actually contribute in combat, but they’re statistically useless. That said, Covenant is surrounded by a wall, so there aren’t many ways enemies can attack - with some careful planning you can build some small platforms along the front (west-facing) wall and mass your own defenses there.
Covenant is limited in other ways, as well. None of the houses or power lines can be broken down, the beds inside cannot be moved or removed. The settlement is also walled-in and irregularly shaped, and while the walls are useful against external threats, they’re another limitation you’ll have to build around. The external boundary of the build area extends for one tile to half a tile from the wall, so you won’t be building any expansions outside the confines of the walls - again, you’ve got just about enough space to put some small, elevated turret platforms.
All in all, you’ve got enough space to lay down a 2x3 structure in the middle of town, which isn’t terribly aesthetically appealing or practical when it comes to getting around. Building up is certainly an option, as it’ll allow you to build more to the front and (west) and towards the Workshop (south) without blocking anything vital. Fortunately the game doesn’t care about silly things like physics, so you can suspend an entire structure off a single ladder, if you wish. If you want to feign realism, you can always use some Scaffolding Frames, Shack Bridges, or Shack Foundations to create the illusion of support at the expense of ground clutter, if your aesthetic tastes demand it.
Verticality isn’t a perfect solution, however, as the build height for this settlement is limited at roughly the tops of the houses; assuming you build up high enough off the ground to walk under your structure, you’ll be able to build two storeys off the ground. Even then, there will be compromises, as much of the second floor will be above the build limit - anything anchored to the ground, like beds, crops, floor and wall tiles will suffice, but don’t plan on hanging anything on the wall or from the roof… fortunately, yes, you can build roof tiles.
There is no standing water, so no Water Purifiers, but aside from the houses, most of the ground is dirt and hence suitable for planting. This is a good thing, as the base garden plot the settlement starts with isn’t sufficient for the needs of its current settlers, much less any new recruits. You can, with many compromises, stuff a lot of settlers into Covenant, just don’t expect to be able to do everything you can at other, larger, more forgiving settlements. Take what you can get, stick Scavenging Stations and beds in every suitable space, and don’t let the perfect be the enemy of the functional.
Or, failing all that, scale down your expectations for Covenant mightily and keep it a small, less developed settlement. There are plenty of better settlements out there to spend resources on.