As far as anyone knows the Chosen do not have a homeworld or anything which one might even consider a base of operation. This can be attributed to the nature of Chosen organization, which tends to consist of many different pilgrim fleets, only setting up colonies long enough to build up their fleet before moving on. This process however can take decades so one can generally pinpoint temporary Chosen strongholds at any given time. These "strongholds" are often chosen for mineral wealth with little concern for the current occupants, this has lead to a large number of altercations with the UCI as their territory tends be "preferred" over that of the other empires. This however is generally not the case when the fleet is lead by a Harbinger, but there are always exceptions.
However there is a place within Chosen lore that they consider to be their true and only home, the place in which their bodies and minds were first forged by Garnlathian. A place many of the Chosen spend entire decades searching for. The Chosen have no true language as far as humans can comprehend however when asked First Born will often equate it to Eden, a veritable paradise from which man was cast out of by god. However the concept of Chosen running through fields of grass an nature is highly comical. First Born often describe it closer to what one might consider a hell. A world of fire and huge plains. A world of crushing gravity blanketed in a poisonous atmosphere. Despite this place sounding somewhat unappealing to the average tourist A race of cybernetic spacecraft would find such a place most desirable. Encased in metal bodies workers need not worry about the worlds many dangers and might simply plunder its riches. This is not the reason for their desire to find this Eden, rather the rediscover of their creator Garnlathian for it was he who cast the first from Eden stating that they were not ready and that only once they had completed their true purpose would they find Eden, before wiping their memory banks of its location and casting them to the corners of the galaxy. this task remains unknown to the Chosen but many have felt something they have not ever felt it is something the first born find difficult to explain to organics but it is a new feeling. Which gets stronger with every passing year, every month,every day and every hour. Like the end of some great journey is nearing its end but when and how are still unknown.