Trishuli valley is among the most popular trekking routes and geologically interesting parts in the Nepal Himalaya. The area comprises both the Lesser and Higher Himalayan rocks. As the area can be easily approached from Kathmandu, it has been the subject of interest for many geologists and students. This book provides a geological map, lithostratigraphy and structural description of the area. We hope that this book will serve as an important guidebook for the researcher as well as the students going for geological excursion along the Trishuli valley.