The Chamra Vortex was a nebula in the Gamma Quadrant, in the Rakhari sector. The vortex had millions of asteroids and was riddled with pockets of toh-maire gas.
Croden hid his daughter, Yareth, in a stasis pod in a large asteroid in the Vortex in 2360s. During his imprisonment on Deep Space 9 for the murder of Ah-Kel, Croden told Odo that there was a Changeling colony in the Vortex.
Odo and Croden traveled to the Vortex, where they rescued Yareth. Ah-Kel followed and attacked them, but his weapons fire ignited the toh-maire gas, destroying his ship. (DS9: "Vortex")