During present investigation a total of sixty specimens of lichens were collected from Balh valley. The lichens were collected during November 2018 to February 2019 from twenty eight localities of Balh Valley in Mandi district of Himachal Pradesh, North Western Himalaya. A total of nineteen species of lichens were identified on the basis of morphological and anatomical characters. Relevant literature was consulted for confirmation of species identification. Out of the identified species, one species viz.Usnea longissimais being reported for the first time from Mandi district. Phaeophyscia hispidulais most common out of the nineteen species and is found in fifteen localities. The species diversity index (α, β, ?) of all the localities was calculated. The highest alpha diversity (four) was found in Bagla and Kasarla. The lowest alpha diversity (one) was found at Bhour, Chakker, Kansa, Nagchala and Pairi. Beta diversity of all localities was 47 and gamma diversitywas 19. The identified specimens have been deposited in CPUH (The Herbarium, Department of Biosciences, Career Point University Hamirpur) for preservation and future reference.