Eminiar VII was the inhabited seventh planet orbiting the primary Eminiar. It was the homeworld for the Eminians, a pre-warp humanoid species. In the 23rd century, Eminiar VII was the principal planet of the NGC 321 star cluster. (TOS: "A Taste of Armageddon")
For over five hundred years, the Eminian Union was the planetary government of this world. This government was headed by the First Councilman of the High Council of Eminiar. The council conducted its governmental duties in the Council Room, which was located in the Division of Control. There was a direct channel between this council and the Vendikar High Council, which, by 2267, hadn't been used for centuries. In 2267, the First Councilman was Anan 7.
The civilization was advanced, having had space flight for several hundred years, but it had elected not to venture outside of its star system.
Eminiar VII had been fighting a war with Vendikar, its colony on the third planet in the system, for five hundred years. The conditions of this war were stipulated in a treaty signed by both worlds. This was a simulated war with casualties determined by computer projections, and the people willingly killing themselves in disintegration stations. Every year, on Eminiar, one to three million were killed by this process. Legitimate targets in the war included vessels orbiting the planet, a fact that caused Kirk considerable difficulty during his visit. The reneging of this treaty by either side could result in a real war.
In 2267, the USS Enterprise visited this planet on a mission to open diplomatic relations with Eminiar VII. During the visit, when his ship and crew were threatened with the same fate as the Valiant, Captain James T. Kirk ended the war abruptly by destroying the computers that were conducting the simulated war. Ambassador Robert Fox began work with the two planets to create a lasting peace and to establishment of a Federation treaty port. (TOS: "A Taste of Armageddon")
In 2268, when held captive by the Kelvans, Captain Kirk asked Lieutenant Commander Spock if he could repeat what he did with the guard on Eminiar VII by tricking him into believing the landing party had escaped. The attempt worked, but only briefly before the Kelvans recapture the landing party. (TOS: "By Any Other Name")
In 2328, three individuals arrived to the Eminiar VII Starbase from the Elba II Orbital Transit Station via commercial transport. Niel Wray and William Foster on the SS Kogin and David Ramirez on the SS Wisconsin. (TNG-R: "Inheritance", okudagram)
Lieutenant Commander Richard James, a crewmember aboard the USS Enterprise-D and USS Voyager, was born on this non-Federation planet. In 2369, this planet was listed on the chart USS Enterprise Personnel Database, which was seen on Jean-Luc Picard's PADD on aboard the Enterprise-D. (TNG: "The Chase", okudagram)
In 2375, a view of the surface of Eminiar VII was depicted on several viewscreens on Deep Space 9's Promenade and Replimat advertising a trip to the "scenic Eminiar VII". (DS9: "The Muse", "What You Leave Behind")