Columbia is a census-designated place in Howard County, Maryland, United States, and is one of the principal communities of the Baltimore–Washington metropolitan area. It is a planned community consisting of 10 self-contained villages.
Columbia began with the idea that a city could enhance its residents' quality of life. Creator and developer James W. Rouse saw the new community in terms of human values, rather than merely economics and engineering. Opened in 1967, Columbia was intended to not only eliminate the inconveniences of then-current subdivision design, but also eliminate racial, religious and class segregation.
Columbia proper consists only of that territory governed by the Columbia Association, but larger areas are included under its name by the U.S. Postal Service and the Census Bureau. These include several other communities which predate Columbia, including Simpsonville, Atholton, and in the case of the census, part of Clarksville. The census-designated place had a population of 99,615 at the 2010 United States Census. It is the second most populous community in Maryland after Baltimore. More recent estimates by the U.S.