The State Archive of the Russian Federation (GARF) contains a corpus of around one hundred letters sent by Élisée Reclus to Pëtr Kropotkin between 1882 and 1905. The correspondence is mainly concerned with their geographical works, notably the collaboration of Kropotkin with the Nouvelle Géographie Universelle (1876e1894) and the Brussels edition of Kropotkin's Orographie de la Sibérie (1904), edited by Reclus. In this paper, we deal first with the importance of this source: it is an example of the material work of a network of geographers who were at the same time the founders of the international anarchist movement. We suggest the correspondence falls into two parts: the first period (1882e1886) when Reclus was in exile in Switzerland after the Paris Commune of 1871, and Kropotkin was in prison in France; and the second period (1888e1905) when the two anarchist geographers discuss the role of geographical education, historical geography in Europe and its part in the globalisation of their era. The archive also contains significant evidence of their relationships with British geography: Kropotkin lived in London and joined the Royal Geographical Society and was on familiar terms with leading Fellows, such as John Scott Keltie and Halford Mackinder. The paper addresses the significance of the correspondence for understanding the relationships between geography, politics and public education, and the role of these heterodox geographers in the construction of geographical knowledge. The paper is accompanied by the publication, for the first time, of an edited selection of the letters.