ENBaltic antroponymy is widely spread on the territory which was the part of the Grand Lithuanian Duchy, cspccially hi its Ukrainian part. This fact is confirmed by the memoriał edition of the "Ukraine's Book of Memory" which sets the listš of Ukrainian sokliers tluit were killed hi 1941-1945. As therc aro no other large-scale antroponymical sources, it has bccome a powcrfnl sourcc of antropoymical fmdings. Having worked up the "Ukraine's Book of Memory", one finds out a region, where in early 1900s the concentration of peoplo with Lithuanian surname Ejsmont was set (Zhytomyrs'ka Oblast', Khmelnits'ka Oblast'). The author's field investigations have shown that the modern antroponym is localized in the same territory (but native speakers take it as an Austrian or a Jewish one). Such zoning of the surname is interpreted as a result of migratory movement of impoverished Polish gentry in the lAth-l§th centuries after Ukraine has become a part of Rzecz Pospolita. Since 17th century, along with Ejsmont, the documents have set the family of Esymontows 'ky, Cossack gentry of Chernihiv. The duality of the Baltic name, functioning on the East-Slavonic basis, illustrates the opposition of presence/absence of the connective vowel -i- in disyllabic Lithuanian antroponyms (Ejs-mont/Es-i--montows'ky). K.Būga has pointed out that oikonyms arising from dibasic surnames often functionate in plural. The realization of this model is traced in Lithuanian-Byelorussian boundary.It is confirmed by M. Fasmer and "Słownik geograficzny Królew-stwa Polskiego": village Ejsymonty Wielikie / Ejsmonty Wielikie (Bogorodyts'ka Volost' Grodnens'ky Povit), village Ejsymonty Malye / Ejsmonty Malye (Mal-oberestovyts'ka Volost' Grodnens'ky Povit), village Ejsymonty / Ejsymonty Nadto-bolskie (Vertslyashkivs'ka Volost' Grodnens'ky Povit). Compare with modern antroponyms: village Ejsmanty Wyalikiya (Berestovyts'ky Rayon Grodnens'ka Oblast', Belorus') and village Ejsmanty (Vertslyashkiws'ky Rayon Grodnens'ka Oblast', Be-lorus') (1982). Given proper nouns, as the surnames, spread in the Ukrainian territory, are the evidence of the process of loss of the connective vowel -i- (as possible method of onym's shortening): at first, single falling out of the connective vowel and simultaneous functioning of both phonetic variations (Ejs-y-monty / Ejs-monty), and subsequently, its absolute disappearing. Furthermore, in word-formative context, the spatial modification of derivative structure of the proper name is traced. The family of Ejsymontows 'ky had founded a village Symontowka (Mglynovs'ky Povit Chernyhivs'ka Guberniya, nowadays — Brans'ka Oblast', Russia). In the course of time, it has consequently come into the line of Ukrainian derivational suffix antroponymical oykomyms: Domon-towka (Skvirs'ky Povit Kyivs'ka Guberniya), Korbutowka (Zhytomyrs'ky Povit Volyns'ka Guberniya), Montwidowka (Kupyans'ky Povit Kharkivs'ka Guberniya), Gedrimowka (Odes'ky Povit Khersons'ka Geberniya). (Change of derivational type: Pluralia tantum —>binomial stem + -ow- + -k-).Consequently, a peculiar "corridor" of the proper name's spreading (and correspondingly, the probabilistic migratory way of its bearers: Lithuania — Grodnens'ky Rayon — Chernihivshchyna) have appeared. Furthermore, the way of "coming" of the Baltic lexeme to Ukrainian language space is traced (probably, in the process of moving away from the Lithuanian boundary and the forms of Pluralia tantum; at first, there could be forms of Domontowo, Korbutowo — nowadays there are such settlements in Ukraine and Belorus' — and *Esynmtowo; afterwards Domontowka, Korbutowka and *Symontowka appeared as secondary settlements). As a result, the origin decoding of Symontowka (and other antroponymical oykonyms) becomes easier (or more difficult?) because of the village proprietors — the family of Esymontowsky. Most likely, the form of the surname, in its turn, has become the result of antroponymical derivation (compare: Radywylows 'ky <— Radywylow).