The establishment of the origin and the meaning of the name of the principal city in 'Suwalki' Region is a difficult task. Due to the history of this region, the investigator shall take into consideration that the names may originate from four languages: the Jacwieski, the Lithuanian, the Belarusian, and the Polish languages. Therefore, as regards the isolated names or names with an imprecise semantic meaning and morphological structure, the researcher shall take into consideration each of the four above-mentioned opportunities of the origin of the said name and only after the elimination of three of them, the researcher may establish the proper linguistic source of the considered name. This being the case, the name 'Suwalki' is neither of Polish, nor Belarusian, nor Jacwieski origin. The name 'Suwalki' is of the Lithuanian origin. Originally, it was the name of the village established on the southern-western border of the then Lithuanian linguistic area in 1682-1690. Due to the above, the said name is connected with the names of villages located on the territory of Lithuania and in the light of Lithuanian linguistic facts it has a transparent structure and a clear-cut meaning. The name consists of the prefix 'su-' and the stem '- valk-'. The Lithuanian prefix 'su-' has a meaning of location 'at', 'near'; the stem '-valk-' occurs in the general Lithuanian noun 'valka' which here has a geographical meaning 'a tiny, small river, a damp and swamp place'. The name of Suwalki means the 'locality located near the damp and swamp place' or even 'near the lake'.