Its forces are held in the fortress of Westkeep and are currently led by the Watch Commander Jotunn. Though the Imperium's records do not detail the identity of the "Picket" that the fortress was named after, there is evidence that it was originally constructed in the Age of Strife and was discovered by the Imperium during the Great Crusade. At that time, the Imperial Fists Legion claimed ownership of the starfortress and built the fortress Westkeep there atop the ancient ruins. The Legion used the fortress as an outpost to stand guard over the Damocles Gulf, but their reasons for doing so have been lost to the ages.
For millennia afterwards, their fortress was maintained by Servitors until the rise of the Tau Empire. The Tau's expansion soon led it into conflict with the Imperium and the outpost found itself on the front lines of their battles. This led the Deathwatch to lay claim to the station and they then heavily added to Westkeep's defenses and weaponry. Despite this though, Picket's Watch's chief defense is the secrecy of its location.