We know what counties and municipalities are. But what are special districts?
Special districts are independent government units created for a limited, specific purpose and, every year, new districts are created and existing ones dissolve.
Special districts typically have a shorter lifespan and higher turnover than general purpose governments, but the difference in their counts was also relatively slim between 2012 and 2017.
This article provides information about type and function of special purpose districts in the United States. Read about special district governments in your hometown in the 2017 Census of Governments: Individual State Descriptions report.