The study aims to identify the features and uniqueness of the ethnolinguistic picture of Southern Russia and to substantiate the origin and composition of regional toponymics, as toponyms are a key code / source of information in the historical landscape. They are recorded in documents, lexicographic sources, atlases, as well as in narrative sources related to the southern territories of Russia. The article describes the history of the appearance of Slavic, Turkic, Adyghe, Dagestani, Iranian, and other peoples in the territory under consideration, the processes of ethnic migrations, and the current state of the population of the southern regions of Russia. The scientific novelty of the study lies in the fact that it provides, for the first time, a comprehensive overview based on chronological facts of the presence of historically formed ethnic groups in the southern regions of Russia as sources of the toponymic picture. This picture is generally represented by the names of settlements, rivers, and mountains. As a result, the historical preconditions for the emergence of appellative-onymic complexes in such regions of the Russian Federation as the Republic of Adygea, Volgograd Oblast, the Republic of Dagestan, and the Republic of Kalmykia are substantiated.