Himachal Day and Himachal Statehood Day, the often conflated and cross-confused annual celebrations days of HP, are the state days of Himachal Pradesh.
Himachal Day is celebrated annually on April 15. Himachal Pradesh came into existence as an official political entity of the Republic of India on this day in the year 1948. The Province of Himachal Pradesh, officially as 'Chief Commissioner's province of Himachal Pradesh', was formed after the integration of 28 hill princely states. To enforce the merger of the disintegrated and fragmented princely states, on 26 January 1948, the Himalayan Prant Provisional Government (हिमालय प्रांत अनंतिम/अस्थायी सरकार) was made under the presidentship of Shiva Nand Ramaul with headquarters at Shimla (then Simla).
Himachal Pradesh Statehood Day (or simply Himachal Statehood Day) is celebrated annually on 25 January. On 18 December 1970, the State of Himachal Pradesh Act was passed by the Parliament of India, and a new full-fledged state came into being on 25th January 1971 as the 18th state of the Indian Union. Hence, the 25 January is celebrated as Himachal Statehood Day.