Municipal charter
A city charter or town charter (generically, municipal charter) is a legal document establishing a municipality such as a city or town. In the United States, such charters are established either directly by a state legislature by means of local legislation, or indirectly under a general municipal corporation law, usually after the proposed charter has passed a referendum vote of the affected population.
United Kingdom
In the United Kingdom, towns and cities are established by royal charter; see city status in the United Kingdom.