Frederick is a city located in the U.S. state of Maryland. It is within Frederick County included in the Baltimore–Washington Metropolitan Area. It has a total area of 23.33 square miles at 39°24′50″N 77°24′40″W. The elevation is 302 feet above sea level. As of the 2010 census data, it had a total population of 65,239. The population density was 2,800/sq mi. Estimated per capita income in 2016 was $34,426. Frederick has Zip codes 21701-21709.