The Barn House is a abandoned barn found outside of Beach City, over in the farming country. It belongs to the DeMayo family, and as such belonging to Greg Universe, Andy DeMayo, and Steven Universe, though this was until after Andy's visit, which he gave the barn to the Off-Colors as their home.
The Barn house is situated out in the countryside, a old dirt road leading up to the main barn itself. Across from the barn is an old silo, and a wooden fence bordered the property facing a nearby forested area. It's seemingly close to an active farm, as cows can be found not too far from the property, and during projects had to be chased away by Garnet.
The interior of the barn is where multiple objects and metal pieces were stored by the DeMayo family. Numerous objects could be found inside, varying from standard trinkets to parts more commonly found on aerial planes. On its first discovery by Garnet, the whole interior of the barn was filled to the brim with many objects, but after many of the parts were worked for the Galactic Ray, much more space was created inside.
According to Andy DeMayo, the barn house was originally owned by the DeMayo family, as it was a spot for traditional family get-togethers, something none of the Crystal Gems knew about as the family had been apart for years since he left. Since the family separated, the barn appeared abandoned.
Garnet stumbled onto the barn prior to the start of the Galactic Ray project, and it was the main site for said production, as many metallic parts were used from said barn in order to help make the spaceship. The area also became a commonplace for training sessions and meetings with the Crystal Gems as of Season 3, namely when the meeting involved the entire team as the Crystal Temple was too small. As of Season 4, it became the birthplace for the first true Gem Fusion hybrid, Stevonnie.
It became the main project spot when the Crystal Gems had to build the Gem Drill, and once the main project was done, ended up frozen in place when Lapis Lazuli isolated herself inside for the remainder of the season.
As of Season 6, the Barn House became the new home for the Off-Colors.