This guide provides a starting point for researchers to access United States Census Data online. Additional census material is located in Lamont, Level B.

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Diane Sredl

Data Reference Librarian, Lamont Library


Understanding and Accessing Census Data

What is the Census? 

The United States has conducted one national census every ten years beginning in 1790.  The U.S. Constitution mandates a decennial Census for the purpose of Congressional reapportionment.  The data collected have changed over the decades, and it is important to note these changes when comparing data over time.  An additional nationwide survey, the American Community Survey (ACS), began in 2005 in an effort to provide detailed information more frequently.

Getting Census Data

Here are some useful tools for finding both summary level and individual level census data, with context on when you might choose one tool over another. 

Summary Level Census Data

Social Explorer
Presents current and historical census data for the United States through the use of interactive maps and reports. Currently provides access to data from 1790 to present at census tract, county, state and national level. They also pull in data on a number of specialty topics, such as US business patterns, housing price index, crime data, employer household dynamics and more. Social Explorer is particularly good for historical census data. 

National Historical Geographic Information System (NHGIS)
Provides aggregate census data and GIS-compatible boundary files for the United States beginning in 1790. The NHGIS database more easily allows you to create time-series data tables. 

Policy Map (TRF)
Fully web-based Geographic Information System. It captures data in visually powerful ways through custom demographic maps, tables, reports and an analysis tool called Analytics. PolicyMap's GIS mapping services can incorporate your own data and leverage it against the thousands of indicators already available. Available data includes demographics, home sale statistics, health data, mortgage trends, school performance scores and labor data like unemployment, crime statistics and city crime rates.

SimplyAnalytics (Geographic Research, Inc.)
Enables creation of maps and tables for the United States that incorporate data such as population, age, race, income, employment, and education.Harvard subscribes to premium content including Experian Simmons Local for market research data and D&B for business demographics.

United States Census Bureau
You can also use data.census.gov to generate tables from the 2020 U.S. Census and other Census Bureau surveys, but there is no advantage to using this website compared to the tools above.  The Census Survey Explorer can help you discover U.S. Census Bureau surveys or censuses by filtering and searching by geography, frequency, topics, and subtopics.

Individual Level Census Data

Integrated Public Use Microdata Series (IPUMS-USA)
The Minnesota Population Center at the University of Minnesota collects, preserves and harmonizes U.S. census microdata and provides easy access to this data with enhanced documentation. Data includes decennial censuses from 1790 to 2010 and American Community Surveys (ACS) from 2000 to the present.