Geographical extension of Kamarupa is the very important and major phenomena of political history of Pragjyotisa-Kamarupa with extension in Pundravardhana, a prestige that is earned by the Bhauma Naraka kings of Pragjyotisa-Kamarupa kingdom from the 4th to 12th century AD. The river system has also left its mark in shaping the geographical divisions and administrative units of both Kamarupa and Pudravardhana area. The resultant political changes are also equally responsible for the administrative changes as is evident from different land-grants. Here in this book, alongwith the study of geographical extension, a historical study has been done elaborately with considerable details of administrative changes as major events. In addition, there is an attempt for a historical study of Pudravardhana, which was under the control of Pragjyotisa-Kamarupa during that period, and of its socio-economic and educational excellence also. The author, a retired Civil Servant from Assam and a PhD on ancient Indian History from Gauhati University, has shed light on the topic which has never got enough justice by the early historians.