The Fort of the Federal Star (Fortín de la Estrella Federal) is the southernmost point the United Platforms of the Plata Estuary claim as their own. Beyond its stockade lie the unnamed pampa and the chiefdoms that pay no tribute.

It is a punishment post: officers whose faults the regime will neither fully forgive nor display in the capital are sent there. Its declared function is border watch; its real one is to hold what the hierarchy wants kept away — troublesome men, awkward news, missions with few witnesses. The garrison reports to the Palace of Mud, an intermediate base to the north, too distant for orders to arrive on time. Expeditions to the south set out from the fort.

The Rosist capital operates under the name Santa María de Torregrises.