The United States Census is conducted every 10 years, and is mandated by the Constitution of the United States (if you're truly interested, you can review Titles 13 and 26 of the US Code for more information).  This census of the population - literally, a count of every person living in this country - is used to allocate Congressional seats, electoral votes, and federal funding of programs.  

It is important to remember that information collected in the census can result in redistricting.  This can directly impact (among many other things) elections, federal and state expenditure, school district boundaries, and infrastructure.

Participation in the census is mandatory for all persons living in the United States.

The US Census Bureau maintains an enormous dataset of information on its website.  This data is culled from the decennial census, as well as interim surveys conducted by non-profit and governmental agencies.  By searching against this dataset, you can locate census tracts, voting districts, demographic information for individual neighborhoods, election outcomes, etc.

Use American FactFinder on the Census Bureau website to view this information.

Enter a city or town name, street address, and/or zip code in the box under "Community Facts." 

Then, click GO.

The US Census Bureau maintains a historic collection of the Census of Population and Housing.  This collection includes selected data from the very first census (conducted in 1790) to today.

You will note that the formats of these early census documents may be very different from year to year.  In addition, much of the data is unavailable in digital format.  If you have trouble using these digital documents, or wish to view print copies, please contact a librarian at the Haas or Young Libraries for assistance.