The Ikalian asteroid belt was an asteroid belt. Some of the asteroids had deposits of actinides.
In 2367, Kriosian rebels, fighting to regain their independence from the Klingon Empire, hid in the Ikalian asteroid belt, using the actinides to hide from sensor scans. While hiding in the belt, they attacked a Ferengi freighter and a Cardassian freighter. (TNG: "The Mind's Eye")
According to the script, the pronunciation for Ikalian was "ih-KAY-lee-n". [1]
According to the Star Trek Encyclopedia (4th ed., vol. 1, p. 358), the Ikalian asteroid belt was located near the Kriosian system.
This asteroid belt might presumably be located in the Ikalia system, which was located in the Beta Quadrant.