Ruah IV was the inhabited fourth planet in the Ruah system. This planet was classified as M-class. 67% of its surface was covered with water, and multiple animal species lived on the land mass, including a genus of proto-hominids. As of 2369, the planet showed no signs of any prior civilization.
Ruah IV was visited by Galen in his quest to solve the mystery surrounding the ancient humanoids before he traveled to the USS Enterprise-D. Following Galen's death, the Enterprise visited Ruah IV in an attempt to discover the puzzle that Galen was in the process of unraveling. Unable to ascertain why he traveled there, the Enterprise proceeded to Galen's next destination, Indri VIII. (TNG: "The Chase")