According to the United States Census Bureau, the place has a total area of 14.1 square miles (36.5 km²), of which, 13.8 square miles (35.8 km²) of it is land and 0.3 square miles (0.7 km²) of it (1.85%) is water.
There were 604 households out of which 42.1% had children under the age of 18 living with them, 72.0% were married couples living together, 6.6% had a female householder with no husband present, and 17.5% were non-families. 13.9% of all households were made up of individuals and 4.6% had someone living alone who was 65 years of age or older. The average household size was 3.04 and the average family size was 3.34.
In the area, the population was spread out with 29.3% under the age of 18, 4.8% from 18 to 24, 29.7% from 25 to 44, 27.4% from 45 to 64, and 8.8% who were 65 years of age or older. The median age was 38 years. For every 100 females there were 100.2 males. For every 100 females age 18 and over, there were 103.6 males.
The median income for a household in the area was $88,419, and the median income for a family was $91,216. Males had a median income of $63,125 versus $42,283 for females. The per capita income for the area was $33,174. About 3.4% of families and 4.6% of the population were below the poverty line, including 6.3% of those under age 18 and 6.8% of those age 65 or over.
In the years since 2000 there has been major growth in the area of Clarksburg. The new town center is currently being built in the heart of Clarksburg. While there is no exact data on the population of Clarksburg currently, there are estimates of about 1400 new residents now living in the new Clarksburg Town Center.
| School Name | School Enrollment Capacity | School Enrollment As of 2006-2007 | Projected Enrollment (2011-2012) According to MCPS | Percent Increase From '06-'07 to '11-'12 | Percent Above/Below School Enrollment Capacity For 2011-2012 |
|---|---|---|---|---|---|
| Clarksburg Elementary School | 335 students | 385 students | 469 students | 21.8% increase | 40.0% above capacity |
| Clarksburg High School | 1629 students | 999 students | 1479 students | 48.0% increase | 10.1% below capacity |
| Little Bennett Elementary School | 685 students | 531 students | 1174 students | 121.1% increase | 71.4% above capacity |
| Rocky Hill Middle School | 956 students | 977 students | 1250 students | 27.9% increase | 30.8% above capacity |