In general, this article reveals the political meaning of administrative reforms and administrative divisions in some countries of Europe and Asia. A special subject of research is administrative reform and the reform of regionalization in the unitary countries, their path to regionalism and greater democratization at the level of regional governance. Administrative reform and the reform of decentralization of power have ripened in Ukraine for a long time, and even at the present stage, these reforms are inherent in some problems. This work reveals all the functional and historical-ethnographic content of administrative reform in Ukraine. The study offers a pilot map of the administrative division of regions and subregional entities in Ukraine, according to Western trends in administrative division. The historical, national foundations of administrative reform and decentralization reforms in Ukraine are interesting, as well as external factors such as European integration, which may affect the formation of the concept of administrative division in Ukraine, both from a historical retrospective and futurism in this matter, as well as from a functional point of view. In general, the Ukrainian space is inherent in some uncertainty and differences in conceptual issues of reforming the administrative-territorial structure of the state. The study analyzes promising developments in the field of reforming of the administrative-territorial divisions and suggests some new trends in possible areas of reform. First of all, the author is trying to restore order about how European trends and ideas can be expressed in the domestic environment. Some legislative initiatives are analyzed and it is proposed to highlight the historical and functional meaning of the concept of a region in legislation. It also analyzes the possible impact of administrative reform on the reforms of various branches of government. In general, the study proposes a qualitative modernization of the system of administrative-territorial construction in Ukraine. In fact, reforming the administrative-territorial structure on the basis of universally recognized world trends can significantly streamline national, regional, subregional and local governance in Ukraine, and bring it to a new level. Also, these reforms carry some modernization of regional economic policy, which the domestic space needs in the face of modern problems.