The article examines the ideas about space that have developed in Russian historical and song folklore. In the poetics of the epic song genres of Russian folklore, namely, in epics and historical songs, space plays an important role, defining “one’s own” and “alien” (“other”) worlds within one of the main mythologemes. Natural space (forests, rivers, seas, mountains, caves, etc.) mark the “other” world; cities — “one’s own” (“human”) at the mythological level. Historical ideas about space arise in heroic ballads, which, according to the concept of V. Ya. Propp, are an example of the state epic. Accordingly, the “own”/“foreign” mythologeme is already determined by the content “Russian world”/“enemy world” and is filled with real toponyms. In historical songs, there is a fundamental replacement of the former generalized type of historicism (epic) by concrete historicism, which affects the toponymic system. A number of examples raise the question of the correspondence or non-correspondence of the toponym in epics and historical songs to geographical reality. With regard to the Caspian Sea toponym, the almost complete absence of connections between the geographical name and the real geographical object is emphasized. The notions of the Baltic Sea, as well as of the towns of the Neva-Baltic space (Shlisselburg, Derpt, Revel), turn out to be more firmly connected with real geography. Shifts in the naming of geographical objects are specially considered: Khvalynsk/Caspian Sea; Varangian/Virian/Baltic Sea; Oreshek/Shlisselburg; Yuryev/Dorpat; Kolyvan/Revel.