Hromi Cluster
The Hromi Cluster was a cluster near the Acamar system of the Beta Quadrant. One of the cluster's systems was the Gamma Hromi system. 

In 2256, the cluster's location was labeled on a tactical map on the bridge of the . 

Later that year, this cluster's location was labeled on the star chart "Alpha/Beta Quadrant Overview" in the ready room aboard the . (; )

In 2257, at least one system, the Gamma Hromi system, in this cluster was occupied by the Klingons. ()

In 2259, the location of this system was labeled on a stellar cartography chart that was seen on the 's ready room viewscreen. The borders of this region were colored red, indicating that it was claimed by the Klingon Empire. ()

The Federation had charted, but not explored, several M-class planets in this cluster by 2366, including Gamma Hromi II. That year, the  entered the Hromi Cluster to locate a Gatherer outpost. ()

In 2399, at least one system, the Gamma Hromi system, in this cluster was in or near to Klingon space. ()

Apocrypha

Background information 
Information on the Gamma Hromi system in "The War Without, The War Within" and "Maps and Legends" is from the star charts seen in those episodes.

According to Star Trek: Star Charts (pp. 61, 62) and Stellar Cartography: The Starfleet Reference Library ("Federation Historical Highlights, 2161-2385"), in 2293, the  either passed through the outer rim of this cluster, or passed near to the cluster, when the starship was on a diplomatic mission to Qo'noS.

Apocrypha 
In the backstory to Star Trek Online, in 2404 the Klingon Empire's Chancellor  invoked ancient Klingon claims to the Hromi Cluster and demanded that all Federation citizens evacuate within three months. The Federation refused, and in 2405 the region became the first battleground of the .

In the game itself, the cluster is located in the Xarantine and  sectors of the  in the Beta Quadrant and features various missions and duty officer assignments.

External link 
 

de:Hromi-Cluster
fr:Amas de Hromi
nl:Hromi cluster
Clusters