Traditionally, utilizing census records to research your family tree has involved wading through microfilm copies of the original handwritten pages, produced by the U.S. government to preserve the records from decay. These microfilmed census records are generally available for viewing at Family History Centers, the National Archives, and libraries with large genealogy or local history sections.

Because census lists were typically recorded in order of visitation, searching for a particular family on a microfilmed record can be cumbersome and time-consuming. The U.S. government did create indexes for many census years to assist researchers in locating specific individuals or families in the microfilmed census records; however, not all census records were indexed, and most were indexed only by the head of household — the individual identified to the census taker as the person responsible for the care of the home and/or family. With the recent advent of every-name computerized indexes, however, knowing the name of your ancestor or relative and the state he or she resided in is often enough to take you directly to the exact page and line where your ancestor is recorded.

Digitized images of original census pages are now readily available online, and every-name indexes allow you to click directly from your search results to a digital copy of the original census page where your ancestors were recorded — in the enumerator's own handwriting. Digital images are the best census records available online because they allow you to look directly at the record as it was originally created, without having to worry about whether a modern-day transcriber misread the handwriting or mistyped the data. Digital images also allow you to look at all of the information included on the original census, while transcriptions usually only include some of the most important details.

This is where Internet genealogy research really provides a boost over more traditional microfilm research. The entire U.S. census, including complete every-name indexes and digital images of the microfilmed pages, is available for searching and viewing on the Internet. The most comprehensive collection of U.S. census records is available through a subscription to Ancestry.com, which offers the only complete set of digitized images for the entire available U.S. census (1850–1930), as well as every-name indexes for each year. The largest census collections available online include: