The Kotaba Expanse is a Delta Quadrant region in or near Benthan space.
In 2374, after the lifeform posing as Steth had taken over Tom Paris DNA, it programmed the ship it arrived in to take a coaxial warp jump to the Kotaba Expanse. There, ships of the Benthan Guard arrived to arrest Paris under the assumption he was Steth. (VOY: "Vis à Vis")