Abstract: This article provides the results of research of the territorial arrangement of the largest volost of Udomlya, which belonged to the Novgorod Archbishop prior to Novgorod land was annexed by Moscow. The author conducts localization of the toponymy of volost in accordance to the cadastre of 1498/99, which contained the characteristics of pogosts and dozens volosts. The article leans on the geoinformation technologies. For localization of settlements, the author linked the borders of land dachas and toponymy of the Economic Notes of the late XVIII century. This described the territory of the volost compactly located in northwestern Tver Region of Bezhetskaya Pyatina of the Novgorod land. This article is first to localize the territory of the volost of Udomlya located in northwestern Tver Region of Bezhetskaya Pyatina of the Novgorod land. Characteristic is given to the territories of pogost districts and dozens the volost was divided. The author clarifies the location of the centers of pogosts; most densely populated areas were in the basin of lakes Udomlya and Pesvo and the rivers Sezha and Volchina. It is established that volost included two pogosts – Spassky and Ilyinsky, which ceased to exist as pogost districts by the mid XVI century. The settlement pattern of dozens testifies to the gradual disintegration of the decimar system in volost by the late XV – early XVI centuries.