Secret government warehouses (synonyms: black sites, hidden government facilities, archives; example mythonyms: Site Bravo, The Ravenhouse Facility) are a type of fictional warehouse or archive where a government, or a secret sect of the government, stores items it wants to keep from the public. These items may be records, relics, powerful magical objects, or alien artifacts. Often these are locations that are hidden and guarded.

Secret government warehouses are usually located in remote or hard to reach locations. They may be in deserts, under the ocean, deep within mountains, or located on hidden islands. They are often underground. Consider the region the warehouse is in. Alternatively, these sites could be hidden underneath an other structure, such as a hydroelectric dam, museum, or sewer system.

The entrance to a secret government warehouse may be a hidden doorway. If underground, there may be elevators or massive lifts that lead to the sublevels. As with all large fictional facilities, there may be ventilation shafts that connect various areas and rooms. There may be self-contained subway systems or other means of transit between distant locations within the complex.

Fictional government warehouses often store state secrets, powerful relics, magical items, or other important documents and artifacts. Consider what is being kept at this locations and what must be done to properly store this element. DNA or biological samples, for instance, may require liquid nitrogen freezers. Magical artifacts may require magical containment procedures.