15th April 1948, on the merger or 30 Riyasat HP comes into power of Indian State. After The independence Himachal Pradesh as political entity came into existence on 15th April, 1948. 26 January 1950 with the implementation of the Constitution of India Himachal as a part C state become union territory under Chief commissioner. It was constituted by integrating the princely States of Chamba, Mandi,
Suket, Sirmaur and 26 smaller states known as the Punjab Hill States. Subsequently, in 1954 Bilaspur, which was then a part "C" State, was also merged with Himachal Pradesh. In 1960 District Kinnaur was carved out of District Mahsu which was earlier constituted by merging 27 hill states. After the re-organization of Punjab in 1966, Shimla, Kangra, Kullu, Lahaul & Spiti Districts, Una Tehsil of Hoshiarpur District and Nalagarh Tehsil of Ambala District were also merged with the Union Territory of Himachal Pradesh. On 18 December 1970 the State of Himachal Pradesh Act was passed by Parliament and the new state came into being on 25 January 1971. Thus Himachal emerged as the eighteenth state of the Indian Union. In 1972 Districts of Kangra and Mahasu were reorganized. District Kangra was trifurcated ,Una and Hamirpur Tehsils were made into separate Districts. Some areas of Mahasu District were merged with Shimla District while the others formed the new District of Solan.
