The Benthan system was a Delta Quadrant system in the Delta Quadrant, associated with the Benthans. An entity posing as Steth claimed to be from the fourth planet of this system. (VOY: "Vis à Vis")

This planet might be either Benthos or Bentha.
This system was only mentioned in dialogue.
According to Star Trek: Star Charts (p. 89), the system's primary was a M-class star.