Although lichens significantly contribute to biodiversity and are crucial bioindicators of ecosystem health, their broad diversity is still inadequately studied in several regions. To provide fundamental data for ecological monitoring and planning for conservation, this study assessed lichen diversity, composition, and distribution across the study area. This work was performed in Burachapori Wildlife Sanctuary under the Nagaon Wildlife Division of Assam to document the lichen diversity for the first time. Systematic sampling was used in field surveys at specific locations, and lichen specimens were identified using morphological, anatomical, and chemical characteristics. The study revealed the occurrence of 61 lichen species belonging to 28 genera and 18 families, with crustose types of growth forms being the most dominant, followed by foliose, fruticose and squamulose. Among them, Gyalecta effervescens and Pyrenula expectata are new to India, whereas Herpothallon minutum, Diorygma albocinerascens, Anisomeridium glaucescens, Bactrospora myriadea, Parmotrema stuppeum, Pyxine asiatica, Ramalina capensis, and Ramalina nervulosa are new records to the state of Assam. Microclimatic factors, habitat disturbance, and substrate type were all closely associated with variations in species composition. The findings emphasise the ecological importance of less disturbed habitats in supporting diverse lichen populations and highlight how environmental conditions affect lichen variety. This study illustrates the importance of lichens as indicators for biodiversity assessment and environmental change and contributes to regional lichen surveys with new additions. Keywords: Bio indicators, Lichen diversity, Biodiversity assessment, New additions.