Grid 216 was the Borg designation for a region of space in the Delta Quadrant, near the Kesat homeworld. It was the location of a large Ba'Neth outpost, hidden by a cloaking field.
In 2376, the USS Voyager confronted the Ba'Neth in Grid 216 to obtain information on a weapon that had caused severe neurological damage to Lieutenant Commander Tuvok. (VOY: "Riddles")