The article documents the final stage in the dramatic history of competition between the two great empires, British and Russian, which went on throughout the second half of the 19'h century and came to be known as the “Big Game” in Asia. Contrary to the opinion shared by many English authors, the chief stake in that “game” was not the “jewel of the British Crown” (i. e., India), but possession of control over the vast trading networks and natural resources situated in the heart of Eurasia. Its “field” involved the Near East, Central and Southern Asia, and the Far East, ranging from Turkey to Japan. Virtually unexplored and politically indeterminate, the region of Pamir became the ultimate focus of the rivalry. The main subject of the article are the geographical and geodetic surveys carried out in the Pamir area in the period from the 1860s through 1890s, related to the competition for its possession between Russia, Afghanistan, Great Britain, and China. On the basis of Russian and British archival sources, it reconstructs the history of their negotiations aimed at setting the boundaries of each one’s influence in Central Asia, which took place in 1869—1872. In addition to that, it traces the subsequent development of diplomatic activities and military-geographical expeditions, which eventually made it possible for Russia to include the region of Pamir within its territory whose southern boundary was determined by the joint British-Russian-Afghan Commission in 1895—1896. Particular attention is given to the geographical studies performed by its members, which pro vided a wealth of knowledge about the nature of the Pamir region and its indigenous human population and made possible the geodetic unification of the Russian surface measurements in Central Asia and British triangulations in India.