Longfellow's Cabin

Longfellow's cabin is a a settlement that can be obtained by finishing the Walk in the Park quest.

While in build mode, the player will notice the buildable area is huge, possibly comparable to Spectacle Island, as also here you are able to build on the entire island, and not just around the main building. You can squeeze a few water purifiers around the edges of the island, just before the green border.

Note also that you can create supply lines between the Longfellow's cabin and your old settlements in the Commonwealth, which is a nice detail, as you can use your existing resources for building this new settlement.

To somehow counter the effects of the radioactive fog in the area, building and powering up a decontamination arch should be considered as one of the first priorities when starting on the settlement.

Appearances
Longfellow's cabin appears only in the Fallout 4 add-on Far Harbor.