A federation is a country with a united central government that is made up of separate units that each control its own internal affairs. The United States is one example of a federation.
Many countries, such as Canada, Australia, Mexico and India, are federations. The Forum of Federations is an international organization that strives to share advantages and challenges of the federation form of government among its members. The forum also works with countries struggling to move from more authoritarian forms of government to the more democratic federation model by providing advice and support. Federations allow states with diverse ethnic and cultural groups to unite into strong countries with centralized governments.