As of 2015, the population was 313,414. Its county seat is Ellicott City. While geographically located closer to Baltimore, MD, recent development in the south of the county has led to some realignment towards the Washington, D.C. media and employment markets. The county is home to Columbia, a major planned community of approximately 100,000 founded by developer James Rouse in 1967.
Howard County is frequently cited for its affluence, quality of life, and excellent schools. With an estimated median household income of $108,844 in 2012, Howard County had the third-highest median household income of any U.S. county in 2013. Many of the most affluent communities in the Baltimore-Washington Metropolitan Area, such as Clarksville, Dayton, Glenelg, Glenwood, and West Friendship are located along the Route 32 corridor in Howard County. The main population center of Columbia/Ellicott City was named second among Money Magazine’s 2010 survey of “America’s Best Places to Live. Howard County Schools frequently rank first in Maryland as measured by standardized test scores and graduation rates.
As of the 2010 United States Census, there were 287,085 people, 104,749 households, and 76,333 families residing in the county. The population density was 1,144.9 inhabitants per square mile. There were 109,282 housing units at an average density of 435.8 per square mile. The racial makeup of the county was 62.2% white, 17.5% black or African American, 14.4% Asian, 0.3% American Indian, 2.0% from other races, and 3.6% from two or more races. Those of Hispanic or Latino origin made up 5.8% of the population. In terms of ancestry, 17.7% were German, 13.9% were Irish, 10.6% were English, 7.0% were Italian, and 4.6% were American.
Of the 104,749 households, 39.3% had children under the age of 18 living with them, 58.9% were married couples living together, 10.5% had a female householder with no husband present, 27.1% were non-families, and 21.9% of all households were made up of individuals. The average household size was 2.72 and the average family size was 3.20. The median age was 38.4 years.
The median income for a household in the county was $103,273 and the median income for a family was $119,810. Males had a median income of $82,307 versus $59,128 for females. The per capita income for the county was $45,294. About 2.8% of families and 4.2% of the population were below the poverty line, including 4.6% of those under age 18 and 5.5% of those age 65 or over.
According to the U.S. Census Bureau, the county has a total area of 253 square miles, of which 251 square miles is land and 2.7 square miles (1.0%) is water. It is the second-smallest county in Maryland by land area and smallest by total area.