Vulcana Regar was a city on Vulcan.
During the late 21st century or early 22nd century, Vulcana Regar was the site of the Ka'Tann Conference. One of the top negotiators at the conference was Ambassador V'Lar. One of the attendees was T'Pol, who was in her early schooling on Vulcan, and who had traveled "a great distance" to see the ambassador. (ENT: "Fallen Hero")
Late-24th century Starfleet Academy hopeful T'Shanik was from Vulcana Regar. (TNG: "Coming of Age")
This city was only mentioned in dialogue.
The Star Trek Encyclopedia (3rd ed., p. 551) (published prior to the filming of "Fallen Hero") identified Vulcana Regar as a city.
According to the script of Star Trek, the katric ark was located in Vulcana Regar, which the script additionally identified as a city. [1]