The world’s highest ground based telescopic observatory is located in

The world’s highest ground‑based telescopic observatory referred to in the question is the Indian Astronomical Observatory (IAO) at Hanle, Ladakh, India. The IAO is the high‑altitude station of the Indian Institute of Astrophysics and is situated atop Mt. Saraswati in the Hanle valley at about 4,500 metres above mean sea level, giving it exceptionally clear, dry skies ideal for optical and infrared astronomy. Authoritative summaries note IAO as one of the world’s highest observatory sites and list it among the highest optical telescopes (around the tenth‑highest globally), underscoring its status as a leading high‑altitude ground observatory [1]. National descriptions of IIA explicitly record the Hanle station’s 4,500 m elevation and role as a premier observatory in India [1].

Sources

1. [1] https://en.wikipedia.org/wiki/Indian_Astronomical_Observatory