The Constitution of the United States of America does not mention local governments.  Local governments are created by and regulated by the states.  This means that to speak about cities or other forms of local government in the United States is to speak about fifty different legal and political situations.

The states outline the powers of municipal governments in charters.  There may be:

• special or specific charters;
• general or classified charters (in which the rules may apply to a class of cities,
  often grouped by population size); or
• home rule charters.

The state municipal leagues can provide information about the form of charter provided in state constitutions.

A city charter is the basic document that defines the organization, powers, functions and essential procedures of the city government. It is comparable to the State Constitution and to the Constitution of the United States. The charter is, therefore, the most important single legal document of any city.

Occasionally, a city will seek to revise its charter.  There are several reasons to do so, generally stemming from the fact that a charter affects everything the city government does. It provides the basis for most municipal regulatory functions and for the delivery of municipal services.  For more information, see Charter Revisions.