Since 1648, when the Treaty of Westphalia was concluded in Germany and the sovereignty of the countries was transferred from the kings to the people and the land, until now we have witnessed extensive changes in the political map of the countries and the expansion of the territorial geometry in the world. From Germany, which consisted of 355 autonomous units and later became a single country after the Cold War, to the disintegration of the Ottoman Empire and the collapse of the Soviet Union, this bill and the expansion of the world political map can be seen. After the Second World War and the emergence of nationalism and religious fanaticism, many areas in the world and within countries have called for separatism and separation from the main land and becoming independent. but due to the lack of support from the Spanish government and other governments, especially European governments, this request of the people of Catalonia did not come to the This article, with descriptive-analytical method and nature, using library resources and internet sites, seeks to analyze the separatism of some regions within the countries and the changes made in the political map of the world. The results of the research show that among the reasons for separatism within the countries are ethnicism, political and economic isolation of the separatist region, the rise of the elites of the separatist region, the involvement of regional and extra-regional powers in arousing the public opinion of the separatist region and ... .