A county is a unit of regional self-government in Croatia that includes a natural, historical and social entity, and its role is to perform tasks of regional importance such as health, education, transport and economic development. There are three levels of self-government in Croatia: municipalities, cities and counties, which have their own legal personalities and statutes that regulate important aspects of self-government. The statute defines the jobs, authority of the body, cooperation between units, and the relationship with citizens. Counties have been historically present since the Middle Ages, but they lost their significance throughout history. After the independence of Croatia, a two-tier system of self-government with municipalities, cities and counties was introduced, and the reforms of 2001 made counties units of regional self-government, while state affairs were transferred to state administration offices. Further changes from 2019 decentralized many jobs, reducing centralization and strengthening regional self-government. Municipalities, cities and counties have specific tasks. Municipalities are responsible for local services such as communal services, education and social welfare, while cities with larger populations perform additional tasks. Counties carry out regional affairs, including health, education, transport and economic development. Croatia's territorial organization went through three phases of development, and within this framework large differences were recorded in the size of the counties and the number of inhabitants. Local and regional self-government bodies include representative, executive and administrative bodies. Representative bodies, such as the municipal council, the city council and the county assembly, pass acts and carry out work in accordance with the law and statute. Members of these bodies are elected for four years, and can be recalled in certain circumstances. Executive bodies, such as the municipal head, the mayor and the prefect, are responsible for the implementation of acts and the performance of unit management tasks. Administrative bodies organize and manage affairs, often through heads appointed on the basis of tenders. All acts are passed in accordance with regulations, and their legality is supervised by the competent state body. Regionalization in Europe, stimulated by the action of the European Union and the Council of Europe, has two key waves. The first wave, in the 1960s and 1970s, focused on the affirmation of regional identities, while the second wave, in the 1980s and 1990s, focused on the economic development of regions. The EU supported regionalization through financial instruments and political measures such as the Committee of the Regions, while the Lisbon Treaty strengthened its role. In Croatia, although political regions have not been adopted, there are statistical regions that serve to monitor development and withdrawal of EU funds. The Law on Regional Development from 2009 foresees the establishment of partnership councils at the level of these regions, which include representatives of the public, business and civil sectors. Regional imbalance in Croatia represents a significant challenge, with large differences between developed central areas and peripheral counties. The continental part of the country is more densely populated and better developed, while the coast has a smaller population and weaker economic development. These regional differences cause migration, demographic changes and population decline in smaller counties, while central areas grow. Imbalances create additional centralization, which negatively affects social conditions in less developed areas and increases regional disparities. Local units perform tasks within their self-governing scope and tasks transferred from the state. Self-governing affairs are financed from local funds, while the affairs of the transferred state administration are financed from central sources. Jobs are divided into mandatory (e.g. public services) and optional (specific to each community). The expansion of transferred jobs can increase the autonomy of larger units, while smaller ones lose their independence. This represents a challenge in maintaining the balance between the autonomy of local units and the control of the central government.