Introduction to Census Data
Welcome to the MLibrary research guide for Census and demographic information! Here are a few things you should know before beginning your search for Census data.
The Decennial Census:
The decennial census is a constitutionally mandated count of the population of the U.S. which is conducted by the government every ten years. The count is used for apportioning Congressional seats, as well as many other purposes, such as demographic research, allocating funding, and informing public policy.
The Census has changed greatly over time. Though the first Census in 1790 did little more than count population, over the years it has grown to include many other types of information. Many questions and terminology (e.g. racial categories) have changed over time as well.
The Long Form and the American Community Survey:
Over time Congress became concerned that there were too many questions. In 1940 the Long Form was created as a way of finding out more detailed information (e.g. questions on income and educational attainment) from a sample of the population. The long form of the Census was sent to 1 in 6 households. The 2000 Census was the last time the long form was used. Since 2000, the American Community Survey has replaced the long form. The American Community Survey is an ongoing survey of a sample popuation that will provide us with detailed and more current information.
The purpose of this research guide is to help patrons who need to find Census and demographic information locate the best resources for their needs. This guide has resources to help users with all of the following:
- Current Census Data
- Historical Census Data
- Understanding Census Geography
- How to Make Maps Using Census Data
In addition, if you are looking for one of the Powerpoint presentations or Excel spreadsheets from the older version of this guide, please see the linked research guide "The Grace York Census Aids Archive."
Census Aids Archive