|• Total||42.1 sq mi (109.1 km2)|
|• Land||40.1 sq mi (103.8 km2)|
|• Water||2.1 sq mi (5.3 km2)|
|Elevation||643 ft (196 m)|
|• Density||725.2/sq mi (280.0/km2)|
|Time zone||Eastern (EST) (UTC-5)|
|• Summer (DST)||EDT (UTC-4)|
|GNIS feature ID||0590147|
Eldersburg is located at (39.400802, -76.951475).
According to the United States Census Bureau, the CDP has a total area of 42.1 square miles (109 km2), of which 40.1 square miles (104 km2) is land and 2.1 square miles (5.4 km2), or 4.89%, is water.
As of the census of 2010, there were 30,531 people and 10,844 households within the CDP. The population density was 725.2 people per square mile (280.0/km²). The racial makeup of the CDP was 92.44% White, 3.42% African American, 0.22% Native American, 1.98% Asian, 0.44% from other races, and 0.76% from two or more races. Hispanic or Latino of any race were 1.47% of the population.
According to the 2000 Census, there were 9,138 households out of which 44.1% had children under the age of 18 living with them, 72.2% were married couples living together, 7.1% had a female householder with no husband present, and 17.9% were non-families. 14.8% of all households were made up of individuals and 7.2% had someone living alone who was 65 years of age or older. The average household size was 2.92 and the average family size was 3.25.
In the CDP the population was spread out with 29.1% under the age of 18, 5.9% from 18 to 24, 31.9% from 25 to 44, 23.7% from 45 to 64, and 9.4% who were 65 years of age or older. The median age was 36 years. For every 100 females there were 101.3 males. For every 100 females age 18 and over, there were 98.4 males.
The median income for a household in the CDP was $70,851, and the median income for a family was $75,848. Males had a median income of $51,473 versus $34,728 for females. The per capita income for the CDP was $25,639. About 1.6% of families and 2.4% of the population were below the poverty line, including 1.9% of those under age 18 and 4.6% of those age 65 or over.
Eldersburg is served by the Carroll County public school system. Elementary schools include Eldersburg Elementary, Carrolltowne Elementary, Piney Ridge Elementary, Freedom Elementary School, and Linton Springs Elementary. The middle schools are Sykesville Middle School and Oklahoma Road Middle School and three high schools, Liberty High School, South Carroll High School and Century High School, span across Sykesville and Eldersburg.
- Kenny, Hamill, The Place Names Of Maryland: Their Origin and Meaning ISBN 978-0-938420-28-6
- "National Register Information System". National Register of Historic Places. National Park Service. 2008-04-15.
- "US Gazetteer files: 2010, 2000, and 1990". United States Census Bureau. 2011-02-12. Retrieved 2011-04-23.
- "American FactFinder". United States Census Bureau. Retrieved 2008-01-31.
- Eldersburg Today - Eldersburg, MD daily news headlines, calendar, weather, and more.
- Eldersburg Rogue Runners
- Eldersburg Weather