The problem of interethnic borderland is represented through the influence of the respondents' attitude to the ethnos, language environment, type of their self-identification for interaction. The "borderland" as a description of the socio-cultural specificity of the region where different ethnic and religious groups interact draws attention to the socio-cultural aspects of socialisation and enculturation of the individual. The process of self-identification is an example of the borderland dynamics in the aspect of intercultural communication. We hypothesised that the nature of interethnic interaction and the choice of identity strategies may depend on social and cultural characteristics of areas of residence and the dominant type of identity (civic, national, ethnic). The authors used a sociological questionnaire to conduct surveys in the republics of Sakha (Yakutia) and Khakassia from 2008 to 2012. It is revealed that the specific perception of Russian space boundaries by Russian youth is that it coincides with the borders of the country. Republican and ethnic markers are also of great importance for representatives of titular ethnic groups. Regional patriotism is more typical for natives of Siberia than for the Russians, whose "little homeland" is the whole Russia. The comparison of youth's types on preferences of nonlinguistic and polylinguistic environments has shown that ethnic identity is less significant for all types of young people who are indifferent to ethnic and nonlinguistic environment, though it is valuable for ethno centrists. The socio-cultural features of the regions influenced the attitude of the youth towards the choice of language for interethnic cooperation and formation of a sense of patriotism. In Yakutia, where the Russian ethnic group is smaller than the titular ethnic group, self-identification as a citizen of Russia for the Russian youth is more significant in comparison with Russian in the Republic of Khakassia.