United Earth Embassy

From Memory Alpha, the free Star Trek reference.

The United Earth Embassy was United Earth's permanent diplomatic mission on Vulcan during the 22nd century. The United Earth Embassy was administered through the United Earth Diplomatic Corps, with officers from the United Earth Starfleet serving in numerous operational and support positions.

In 2154, Maxwell Forrest and Vulcan Ambassador Soval visited the Embassy to discuss the preliminary stages of joint missions between Earth Starfleet and the Vulcan High Command. In the course of this discussion, the embassy was bombed and badly damaged, killing at least 43 people – including Admiral Forrest. The bombing was originally blamed on the Syrrannite movement, which the High Command characterized as a terrorist organization. It was later found that the embassy was bombed by agents of Administrator V'Las, who sought to publically discredit pacifist movements such as the Syrrannites as part of his plot to launch a preemptive invasion of the Andorian Empire. (ENT: "The Forge", "Awakening", "Kir'Shara")

Presumably, the Embassy served as the primary workplace for the United Earth Ambassador to Vulcan.

The script and production report for the Star Trek: Enterprise episode "The Forge" at StarTrek.com establish that the United Earth Embassy was in Shi'Kahr.