Howard County is a county located in the central part of the U.S. state of Maryland, between Baltimore and Washington, D.C. The county was named for John Eager Howard, an officer in the American Revolutionary War and Governor of Maryland. As of 2000, the population was 247,842. Its county seat is Ellicott City. The center of population of Maryland is located on the county line between Howard County and Anne Arundel County, in the unincorporated town of Jessup. This county is a part of the Baltimore-Washington Metropolitan Area.

Howard County's largest community is Columbia (though, in fact, this is not an incorporated city under Maryland law; in fact, Howard County has no incorporated municipalities). The northern portion of Howard County is part of the suburban region around Baltimore; the southern is more oriented toward Washington, D.C. The county is approximately the area where the two cities' suburbs overlap. Howard County is also the only "Maryland-locked" county in the state -- it is the only county not bordering the Chesapeake Bay, the Atlantic Ocean, another state, or Washington, D.C.