The Dream Alien's homeworld was an inhabited planet in the Delta Quadrant. It was the homeworld of the Dream Aliens.
After being under assault from the Dream Aliens in 2374, Chakotay found the planet less than a light year from USS Voyager's location by detecting a neurogenic field emanating from the caverns located beneath the planet's surface. (VOY: "Waking Moments")
According to the episode's script, this planet's appearance was described as a "foreboding,
gaseous planet."
According to the Star Trek: Star Charts (p. 88), the planet, named "Dream World" in this reference work, was located in a trinary system of M-class stars. Voyager visited this system on stardate 51471.