The article examines the information on the infuence of Russian newcomers on the border Finnish population of the Karelian Isthmus at the turn of the 19th and 20th centuries. It deals with the villages of this region, where the largest number of Russians was recorded, i. e. next to the Finnish railway line “Saint Petersburg-Riihimäki”, which provided transport accessibility. The aim of the study is to analyze a new vector of Russian-Finnish relations, which developed as a result of a noticeable migration fow from the center of the empire. A social profle of Russian newcomers to the territory of the Karelian Isthmus varies: the capital's intelligentsia, workers, peasants and revolutionary elements hiding from police surveillance. The border factor, that is, the fact that this territory was less controlled by the Russian authorities, made it possible for the revolutionaries to hold meetings, to interact relatively openly with Finnish opposition groups, while avoiding persecution due to noninterference by the Finnish authorities. It is noteworthy that the geography of the migration process was not limited only to the nearby metropolis. There are cases of migrations from Minsk, Yaroslavl and Vladimir provinces, previously neglected in historiography. In addition to dacha resting, entertainment and tourism, the Grand Duchy of Finland provided people with the opportunity to earn money: they bought land from Finnish residents for subsequent resale at a higher price, or they provided various services to meet the needs of summerfolk (construction, maintenance, grocery trade). There were also illegal sales of alcohol by Russians. Since its transportation in the territory of Finland was banned, the culprits could be substantially fned and even imprisoned. Close links with the Russian population impacted the local Finnish residents, who began to mix Russian and Finnish languages, abandoned the traditional peasant way of life and adopted the capital's habits. The turn of the century was marked by reciprocity in the border Russian-Finnish relations, which became more personal and informal afer the parties rejected the stereotypes imposed by the political agenda.