Based on the topical and chronological analysis of archival sources and publications of a prominent Russian geologist, Academician F. N. Chernyshev (1856– 1914), his scientific and organizational activities associated with the exploration of little-known territories of the North and the Arctic in the late 19th – early 20th century are reviewed. In particular, the article analyzes the documents regarding the role of F. N. Chernyshev in the organization of the Russian-Swedish Grade Measurement Expedition in the Svalbard Archipelago in 1899–1901. Chernyshev’s contribution to the preparation and implementation of this international scientific project is pictured, based on the documents from his personal fonds and those of the Academy of Sciences’ Commission for Grade Measurement in the Islands of Svalbard, stored in the St. Petersburg Branch of the RAS Archive. The study focuses on Chernyshev’s expeditionary diaries that are introduced into scientific circulation for the first time. Based on these documents, the Expedition’s route and the course of its scientific research are analyzed and the scientists’ working conditions during the trips to the archipelago are shown. The published works by F. N. Chernyshev and his companions were used as additional sources. It is concluded that Chernyshev’s scientific legacy is an important part of the history of the Russian-Swedish Expedition to the Svalbard Archipelago as well as a valuable source for the studies of Russian exploration of the Arctic territories at the turn of the 20th century.