The correct answer is: 1966.
The High Court of Delhi was extended to the Union Territory of Himachal Pradesh on 26 January 1966. This was done by the Himachal Pradesh High Court Act, 1966. The Act provided for the establishment of a High Court for Himachal Pradesh and for the transfer of certain cases from the High Court of Delhi to the High Court of Himachal Pradesh.
The High Court of Delhi was established in 1916. It was originally the High Court of the Punjab and its dependencies. In 1956, the High Court of Punjab was divided into two High Courts, the High Court of Punjab and Haryana and the High Court of Delhi. The High Court of Delhi continued to have jurisdiction over the Union Territory of Himachal Pradesh until 1966.
The High Court of Himachal Pradesh is located in Shimla. It has jurisdiction over the entire state of Himachal Pradesh. The Chief Justice of the High Court is Justice Vikramaditya Singh Khichi.