A Klingon world near the Romulan border, site of the 2293 peace conference and the 2346 Romulan massacre that orphaned Worf.
Khitomer is a planet in Klingon space near the border with the Romulan Star Empire. In 2293, it was the site of the peace conference between the Federation and the Klingon Empire in Star Trek VI: The Undiscovered Country.
At the conference, conspirators tried to assassinate the Federation President. Kirk and the crew of the Enterprise-A, helped by Captain Sulu's Excelsior, destroyed General Chang's cloaked Bird-of-Prey above the planet and beamed down in time to stop the gunman. The talks went ahead and produced the Khitomer Accords.
In 2346, the Klingon outpost on Khitomer was destroyed in a Romulan attack in which about four thousand Klingons died. A Starfleet officer, Sergey Rozhenko, found the young Worf in the ruins and adopted him. Worf's father Mogh was later falsely blamed for betraying the outpost, a lie that shaped many of Worf's stories in The Next Generation.