Gamma Hromi II
The Hromi Cluster was a region of space near the Acamar system, where a number of M-class planets were located, including Gamma Hromi II. The Federation had charted, but not explored, several of these planets. In 2366, the USS Enterprise-D entered the Hromi Cluster to locate a Gatherer camp. (TNG: "The Vengeance Factor")
According to the Star Trek: Star Charts, on page 61, the Hromi Cluster was located in the Beta Quadrant.