The article is devoted to a multi-aspect analysis of the state border of the Republic of Kazakhstan in order to determine the main legitimacy of its formation. The study used geopolitical, legal, socio-economic, cultural-historical and security approaches that made it possible to get a comprehensive understanding of the nature and role of the state border. The study shows the evolution of the border from physical barriers to complex political, economic and socio-cultural structures, and also highlights the importance of combining modern technologies and international cooperation for effective border protection. In conclusion, proposals are proposed to optimize the management of the border of Kazakhstan in modern conditions.