The Borias Cluster was a region of space in the Alpha Quadrant. It was located within Cardassian territory.
During the Dominion War, several Dominion supply depots were located there. (DS9: "Once More Unto the Breach")
This cluster was only mentioned in dialogue.
This cluster's quadrant of origin is inferred based on the position of the Cardassian Union as seen in the star chart appearing in the Star Trek: Picard episode "Maps and Legends".