Frederick is home to Frederick Municipal Airport (FDK), which primarily accommodates general aviation traffic, and to the U.S. Army's Fort Detrick, the largest employer in the county. Frederick is also home to BP Solar, which is the second-largest employer in the county and one of the largest solar panel factories in the country.
As of the census of 2000, there are 52,767 people, 20,891 households, and 12,787 families residing in the city. The population density is 2,584.4 people per square mile (997.7/km²). There are 22,106 housing units at an average density of 1,082.7/sq mi (418.0/km²). The racial makeup of the city is 79.1% White, 16.0% Black or African American, 0.8% Native American, 3.8% Asian American, 0.1% Pacific Islander, 2.9% from other races, and 2.5% from two or more races. 4.80% of the population are Hispanic or Latino of any race.
For those 20,891 households, 32.3% had children under the age of 18 living with them, 44.4% are married couples living together, 12.8% have a female householder with no husband present, and 38.8% are non-families. 30.0% of all households are made up of individuals and 8.8% had someone living alone who was 65 years of age or older. The average household size is 2.42 and the average family size was 3.05.
In the city, the population has 25.1% under the age of 18, 9.3% from 18 to 24, 35.2% from 25 to 44, 19.0% from 45 to 64, and 11.3% who were 65 years of age or older. The median age is 34.7 years. For every 100 females there are 90.9 males. For every 100 females age 18 and over, there are 87.4 males.
According to sample data from 1999, the median income for a household in the city is $47,700, and the median income for a family is $56,778. Males have a median income of $38,399 versus $27,732 for females. The per capita income for the city is $23,053. 7.4% of the population and 4.8% of families are below the poverty line. 6.8% of those 65 and older were living below the poverty line.
From 1896 to 1961, Frederick was served by the Hagerstown & Frederick Railway, an interurban trolley service that was among the last surviving systems of its kind in the United States.
Currently, the city is served by MARC commuter rail service, which operates several trains daily to Washington, D.C.; Express bus route 991, which operates to the Shady Grove Metrorail Station, and a series of buses operated by TransIT services of Frederick, Maryland.
Frederick has an airport with a mile-long runway and a second 3600' runway. It is the home airport of the Aircraft Owners and Pilots Association due to its proximity to Washington and ability to handle small twin engine jets.