2020 Decennial Census Data
The United States Census Bureau is releasing data from the 2020 Decennial Census on a rolling basis. Loudoun County’s 2020 population was 420,959.
Data on Loudoun County is currently available from these four data releases:
|Census Bureau Release Name||Release Date||Contents||Do PopulationTotals Match the Redistricting Release?|
|Redistricting Data Summary File (P.L. 94-171)||August 2021||Total population, voting age (18+) population, major race groups, Hispanic or Latino origin, total housing units and whether they are occupied, population not in housing units (group quarters population) by major group quarters type.
|Demographic and Housing Characteristics File (DHC)||May 2023||Age, sex, major race groups, Hispanic or Latino origin, household type, family type, relationship to householder, group quarters population, housing occupancy, and housing tenure. Tables showing data cross-tabulated by characteristics such as age and race are included.||Yes|
|Demographic Profile||May 2023||Table which summarizes the data included in the DHC for a given geography (county, town, unincorporated areas known as “census designated places,” and census tract).||Yes|
|Detailed Demographic and Housing Characteristics File-A (Detailed DHC-A)||September 2023||Population by sex and age categories for 300 racial and ethnic groups, as well as 1,187 American Indian and Alaska Native tribes and villages nationwide. Population counts for Loudoun County, its towns, census designated places, and census tracts are shown for a group if there are enough people in that area to meet the Census Bureau’s statistical thresholds. These thresholds allow the Census Bureau to maximize data granularity while maintaining individual respondent confidentiality. Most often 22 people are required, for regional groups such as European, the population needs to be at least 94.||
No, a different way to protect privacy was used, including suppressing data when the population count for a geography is too small. However, data from the redistricting release on major race group, Hispanic/Latino ethnicity, and total population can be used as denominators when calculating percentages.
While the Census Bureau is currently finalizing its future release schedule, it consistently updates its product offerings and release calendar, with the most up-to-date information available here.
Users may find the following Census Bureau resources helpful:
- Interactive Data Map Viewer: A web map application that includes state-, county-, and census tract-level data from the 2020 census
- America Counts: 2020 Census Stories
- 2020 Decennial Census Questionnaire (PDF)
- Handbook designed to help users better understand the 2020 Census Disclosure Avoidance System (DAS), including the use of differential privacy and what to consider when working with the data. The differential privacy approach was used in the first three releases.
The description of the Detailed DHC-A and its privacy approach in the blog What You Should Know About the Upcoming Detailed Demographic and Housing Characteristics File A.
New features of the 2020 Decennial Census include new approaches to protecting the privacy of respondents, and additional detail collected on racial and ethnic groups. Data users should use caution when comparing 2020 Decennial Census race data to data from the 2010 Decennial Census, because of improvements to question design, data processing, and coding procedures for the 2020 Census. The Census Bureau provides more guidance in the materials which accompany each release.
Accessing Online Census Bureau Data
To easily find Loudoun County 2020 census data on the U.S. Census Bureau's data website, type "2020 Decennial Census Loudoun County, Virginia" in the search box. (Alternatively, using the Advanced Search feature allows the user to choose which geographic level, topic, etc. – be sure to select the year 2020 and the survey Decennial Census when using Advanced Search.) The Census Bureau offers training videos as well through its Census Academy, including How to Navigate data.census.gov and 2020 Census Redistricting Data and How to Find it on data.census.gov. More information on how to access the Census Bureau's online data can be found here.
As an example, entering "2020 Decennial Census Loudoun County, Virginia" in the search box brings up a list of all the tables released for Loudoun County as a whole, whether they are from the DHC, the Redistricting release (only six tables, repeated in the DHC), are a Demographic Profile (only one table), or are a table from the Detailed DHC-A.
To limit search results to only one of the releases, use the survey filter at the left to navigate to the release you want. Using the DHC as an example, for Survey select = Decennial Census, then select Demographic and Housing Characteristics.
For the Detailed DHC-A, after you have completed these steps, select “Race and Ethnicity” under Topics. Thereafter, “>” means more detail is available. A check box indicates the maximum level of detail available. All geographies with a population meeting the population threshold will have Table T01001, total population. Three sex-by-age tables also will be listed (T02001 - 4 groups, T02002 - 9 groups, and T02003 - 23 groups). Other than for regional data (European, etc.), when you click on them only one will have data. The other two will have a “data not available” message. This is not a mistake. The Census Bureau provides the table with the maximum level of detail available while still protecting privacy, whether that table has 4, 9, or 23 sex-by-age categories.
- Selected Links to Loudoun County Demographic Profiles
- Selected Links to Loudoun County Detailed Demographic & Housing Characteristics File-A (DHC-A) Data
Analysis of Loudoun County Census Data
- Population Growth (PDF)
- Race and Hispanic or Latino Ethnicity (PDF)
- Housing Units (PDF)
- Maps of Population Concentrations by Race (PDF)
- Map of Population Concentrations by Hispanic or Latino Ethnicity (PDF)
- Maps of Housing Unit Change (PDF)
- Maps of Housing Unit Density (PDF)
- Loudoun County 2020 Census Population Patterns by Race and Hispanic or Latino Ethnicity
2020 Census Data Assembled by the Northern Virginia Regional Commission
For the region and its jurisdictions – see data listed under “Decennial Census Data:”
For the region’s towns – see data listed under “Decennial Census Data:”