Tibet is an Asiatic region located in China, which borders with India on Earth. The Tibetan plateau is located in Tibet. (DS9: "Our Man Bashir")
Jack, a youth from Carbon Creek, Pennsylvania, preparing for college spent a lot of time at the library about places he liked to visit, including Tibet. While discussing meditation with T'Mir, Jack explained to her that his readings, he learned that the Buddhist monks of Tibet meditate every day. (ENT: "Carbon Creek")
In 2151, Captain Jonathan Archer claimed that the oldest monastary that he ever visited was in Ngari, Tibet. (ENT: "The Andorian Incident")
While visiting Earth during the mid-22nd century, Doctor Phlox attempted to familiarize himself with many of the planets religions including Buddhism, which he accomplished by spending two weeks at a Tibetan monastery where he learned to sing chords with the high lamas. (ENT: "Cold Front")