The publication is dedicated to one of the Russian northern seas - the Chukchi Sea, which is part of the Arctic Ocean. The encyclopedia contains about 500 articles on hydrographic, geographical objects and hydrological features of the sea. The most significant natural objects are presented - islands, peninsulas, bays, rivers, their geographical features, economy, culture and history, as well as cities, ports, water, biological resources, international agreements, research institutions, the activities of outstanding scientists, researchers, travelers.