Since a congressional mandate in 1790, censuses have polled different kinds of information. More recent censuses contain more information than earlier ones. Between 1790 and 1850, the ten-year censuses only obtained the name of the head of the household and listed others in the household according to sex and age categories. In 1850, the census began to list the names, ages, occupations, and birthplaces of each person. The 1880 census was the first to list the state or country of birth of each person's parent. The census also began to indicate what the relationship is among those in the same household. The 1910 census was the first to give the month and year of birth. It also includes each person's age, the number of years the person had been married, his or her immigration year, and citizenship status.

Used with permission from The Everything Family Tree Book by William G. Hartley (Adams Media, 1998)

Obviously, the census records are not without error. Although enumerators were given basic instruction as early as the 1820s, few other records are so susceptible to subjective opinions. The enumerators were not always well educated or qualified; often they were simply political appointees who received their assignment because they shared the same political affiliation of the current government leaders. If census takers found no one home, they would sometimes obtain information from the neighbors. Other households were missed entirely, or the information written is illegible or spelled incorrectly. Many people lied about their age, and language often presented a barrier as well. Eventually, the information gathered by the enumerators worked its way back to the Bureau of the Census, where it has been recorded in a variety of ways through the years. Two handwritten copies of each record were made, increasing significantly the chance for errors. Definitions of dwellings changed through the year and adjusting the census for political purposes was fairly common.

The information contained on this page comes from a variety of sources, but relies heavily on The Everything Family Tree Book by William G. Hartley (Adams Media, 1998) and Ancestors: A Beginner's Guide to Family History & Genealogy by Jim & Terry Willard with Jane Wilson (Houghton Mifflin Company, 1997).