Census records are an important tool for family history research. From them you can learn who was living in a household at a given point in time, including spouses, siblings, and possibly even a mother-in-law. Census records can also tell you the approximate age of the individuals, where they were born, and what they did for a living. Some census records also provide detail on an individual's immigrant status, including the year of immigration and whether the immigrant applied for U.S. citizenship. Best of all, every available U.S. federal census from 1790 to 1930 can be accessed online.

Exploring the U.S. Federal Census

The United States began to count its citizens in 1790, not long after its birth as a country. This first federal census, instituted by President George Washington, was intended to provide information on residents for the purpose of apportioning members of the House of Representatives and assessing federal tax. Since that first census, the U.S. government has conducted a federal census, or decennial census, once every ten years. However, data from more recent censuses are not available for public inspection because of a seventy-two-year restriction imposed by law to protect the privacy of living individuals. This means the most recent census currently open for public access is 1930 (the 1940 census will be released to the public and available online on April 1, 2012).

Before 1850, census schedules recorded only the name of the head of household and numbers and approximate ages of any other people living in the home. As the country's population grew, the government's need for additional information also grew and new questions were added to the census. The 1850 census is an important census document for researchers, as it was the first census to list names and ages for all individuals in a household, as well as including the place of birth. Another key year is 1880, as it marked the first federal census to document the relationship of household members to the head of household.

In 1900 the census asked for the month as well as year of birth, providing more detailed information on ages than any census before or since. It is also the first available census record to document immigration and citizenship data, asking whether an individual was foreign born, the year of immigration, the number of years in the United States, and the citizenship status of foreign-born individuals over the age of twenty-one. As the twentieth century progressed, additional questions were added to each census, while others were dropped. Most notable: the 1910 census recorded survivors of the Union or Confederate Army or Navy, the 1920 census asked for the year of naturalization for naturalized citizens, and the 1930 census recorded whether the family owned a radio set.

What the Census Can Tell You about Your Ancestors

While the early censuses were little more than a head count of the population, more modern census records are filled with a wealth of valuable data. Most significantly, the 1850 to 1930 censuses can provide such details as: