Howard County is located in the U.S. state of Maryland. As of the 2020 census, the population was 334,529. Since there are no incorporated municipalities, there is no incorporated county seat either. Therefore, its county seat is the unincorporated community of Ellicott City. Howard County is included in the Baltimore-Columbia-Towson, MD Metropolitan Statistical Area, which is part of the larger Washington–Baltimore combined statistical area.

A county seat is an administrative center, seat of government, or capital city of a county or civil parish. The term is in use in five countries: Canada, China, Hungary, Romania, and the United States. An equivalent term, shire town, is used in the U.S. state of Vermont and in several other English-speaking jurisdictions. County towns usually serve a similar function in Ireland, Jamaica, and the United Kingdom.