Abstract
The present article considers theoretical issues related to singling out of hydronyms inside the toponymical lexics, as well as to understanding the terms “microtoponym” and “microhydronym” in the contemporary Russian science; the informational value of microhydronyms in the linguistic and extralinguistic aspects; the part played by the hydronymic lexics in the description of regional onomastic systems. Exemplified by an analysis of some local names of the Smolensk region (e.g. Oles, Drogonka, Mereya, etc.) the article demonstrates in what way the geographical position of the area and its history influence the formation of hydronymics. Attention is paid to dialectal bases of numerous microhydronyms, their substratum character conditioned by interethnical and interliguistic contacts of ancient residents of the Smolensk region. The article underlines the importance of areal studies in the research of the names of local hydro-objects.