This source study is based on unique archival materials. Translation of a number of manuscripts of the outstanding researcher of Siberia of the XVIII century. G.F. Miller into Russian, their attribution and comparison with other sources are carried out for the first time. The analysis of expeditionary materials carried out by the author made it possible to clarify many controversial issues of the history of the development of Siberia by Russians (dynamics of migration processes, dates of foundation of settlements, size of settlements), as well as the number and settlement of some indigenous peoples