Have you ever thought about how, or why, new roads, schools, after-school programs, or hospitals are placed in communities? What makes communities attractive to new businesses or tourists? Why there is no ATM or bike-share kiosk on a street corner? The answers often lie in the numbers—numbers that reflect what our communities look like, how our communities have changed, and how those changes impact our daily lives.

The U.S. Census Bureau’s American Community Survey (ACS) is designed to answer these types of questions and to meet the needs of policymakers, business leaders, planners, and others nationwide who need good data to make informed decisions. The ACS provides a detailed portrait of the social, economic, housing, and demographic characteristics of America’s communities.

This handbook provides an overview of the ACS to help data users understand the basics of the survey, how the data can be used, how to judge the accuracy of ACS estimates, and how to access ACS data. It also includes some recent case studies that show how ACS data are being used to help address important policy and program issues. Links to additional ACS resources, including technical documentation for more advanced users, are included throughout the handbook.