Data and Mapping


Frederick County U.S. Decennial Census total population for April 1, 2020, was 271,717.

Population estimates are produced for years between decennial censuses and updated annually, with the most recent decennial census used as the base. Frederick County’s estimated July 1, 2021 population was 279,835 residents.

2020 Census Profile

2020 Census Profile Opens in new window

2020 Census Profile of General Population and Housing

2020 Census Population Pyramid

Quick Facts
QuickFacts provides basic count of population for areas with more than 5,000 people; includes April 1, 2020 population.

2010 Census Profile
County, municipalities, census designated places

2010 U.S. Census Populations

Population Estimates

Population Projections

Building Permits & COO’s by Dwelling Type

Monthly Building Permit Reports  

Please note that Frederick County does not issue permits for the City of Frederick or the Town of Mount Airy. Permit data is provided by the City of Frederick for inclusion in this report. Permit data for the Town of Mount Airy is reported by Carroll County, which issues permits for the Town.  

Residential Development Pipeline

Includes all county and municipal projects that have received some type of development approval and may or may not be under construction. Development approvals are derived from approved site plan applications, preliminary subdivision plan applications, or a Phase I PUD/MXD applications (county only). 

  • Approved Units: Total lots/units that have received either site plan, preliminary subdivision, or Phase I PUD/MXD plan approval
  • Developed/Permitted Units: Lots/units that are constructed or have building permits issued
  • Available Pipeline: Total remaining lots/units that have not been constructed nor have permits issued
  • Recorded Units: Total lots/units that have been recorded and may or may not be developed
  • Recorded Units Available: Lots/units that have been recorded but are not developed or have permits issued


Frederick County GIS