The most recent data from the U.S. Census Bureau (2007) counted 39,044 general purpose local governments, which includes 19,492 municipal governments, 16,519 township governments and 3.033 county governments. There are 50,432 special purpose local governments, which includes 37,381 special districts, 13,726 independent school districts, and 1,452 dependent public school systems. For descriptions of each type of government, please visit Local U.S. Governments.

Municipal governments vary widely according to quantity, designation and incorporation requirements (see Forms of Municipal Government for more information), but they generally have similar powers and perform similar functions to one another that differ from those of township or county governments. The U.S.'s 19,492 municipal governments range in population size from very large (over 300,000) to very small (under 1,000).  The vast majority (over 90%) of municipal governments in the U.S. have populations under 25,000. 

The number of municipal governments and their distribution by population size also varies by state.  Illinois, Texas and Pennsylvania have over 1,000 municipal governments, while the District of Columbia and Hawaii have only one.  In Alaska, nearly all of the municipal governments are very small (population less than 10,000).   In Massachusetts and Rhode Island, on the other hand, no municipal government has population less than 10,000.  California's municipal governments are distributed across population sizes, however most of the state's 478 municipal governments have populations between 10,000 and 100,000. 

The chart below from the U.S. Census Bureau shows the distribution of municipal governments by population size in the U.S.  It also shows this distribution by each state and the District of Columbia.

Subcounty Municipal Governments by Population-Size Group and State: 2007

Sources

U.S. Census Bureau, Governments Division, Local Governments and Public School Systems by Type and State, 2007. Washington, D.C.: U.S. Census Bureau. Accessed March 17, 2011, http://www.census.gov/govs/cog/GovOrgTab03ss.html.

U.S. Census Bureau, Governments Division, Government Organization, Table 7: Subcounty General-Purpose Governments by Population-Size Group and State. Census of Governments (2007).