Editor's Note: This article is the first in a two-part series. Read Part 2.

Census returns are one of the most useful and informative of genealogical record sources. For each person in a household, they can contain details of name, age, occupation, and birthplace, and in all but the earliest censuses, relationship to the head of the household is also included. Census information can lead to earlier generations, solve particularly thorny problems, and paint a vivid picture of a community.

To be clear about the subject of this article, two terms require definition. Great Britain refers to England, Scotland, and Wales. It is not the same thing as the United Kingdom (UK). That came into existence in 1801 when the Parliament in Dublin was done away with and Irish representatives were elected to the House of Commons at Westminster. The UK today is made up of England, Scotland, Wales, and Northern Ireland. We’ll be concerned only with the census in Great Britain.

The census was a long time in coming. The first debates on the subject occurred during the 1750s, but the idea was controversial, and although the initiative received enough support in the House of Commons, the House of Lords rejected it. Two arguments were strongly expressed—either the census would severely impair individual freedom or it would give information about national weaknesses to Britain's enemies.

The debate continued. Attempts were made to determine the population from hearth and window tax returns. Opinions were expressed as to whether the population was rising or falling and whether the nation was able to feed itself. The most influential publication was the Essay on the Principle of Population by Thomas Malthus, which appeared in 1798. Malthus was among those urging that a national census be taken.

The public debate and a series of bad harvests in the 1790s helped to influence opinions, and the Census Bill passed successfully in 1800. The first census was taken in 1801, and others have occurred every ten years since, except 1941. In the first census, and through three more to 1831, the person designated as the local census taker in each English and Welsh parish was the overseer of the poor; in each Scottish parish, it was the schoolmaster. These census takers were required to find out how many males and females were in the district, and to obtain some information about classes of occupations.

For the government, there were two main objectives: to determine the population of Great Britain and to find out whether the population was rising or falling. In 1801, church ministers were required to provide reports on the numbers of marriages since 1754 and on baptisms and burials recorded in their registers since 1700. Subsequent reports concerned the years since the last census.

The method of collecting information remained much the same through four censuses. None of these was a list of all inhabitants at each address, however, some enthusiastic enumerators did list more than heads of household. Once the statistical analysis was complete and the report made to Parliament, the returns were destroyed (although some fragments survive).

The format changed in 1841. Responsibility for the census moved to the General Register Office, which had been set up in 1837 to collect the details of births, marriages, and deaths in England and Wales. The country was therefore already divided into registration districts and sub-districts, and these were further divided into enumeration districts, which contained twenty-five to two hundred people. A system of civil registration was established in Scotland in 1855, and in 1860 responsibility for the Scottish census was transferred to this office.

It was a major undertaking to ensure that the census was recorded without duplication, which meant conducting it in the shortest possible amount of time. The local enumerator left a census form at each household several days in advance of census night. These were later collected, and the enumerator would interview a member of the household when collecting the form if no one had been able to complete it. The process did not change much in the subsequent returns. The enumerator then copied the information on the forms into registers, which eventually found their way to London for processing. It is these registers that have been filmed and made available for public viewing.

The instructions to enumerators were clear: no one who was present on census night at a particular address could be left out of the tally, and no person absent from home could be written in. Each person was to be enumerated in his or her location on census night. This is important because many people will not show up in the list of the family at home on census night. Some reasons why people were not enumerated at home include being away at work (e.g., sailors), visiting nearby, caring for a sick relation, or traveling.

There were other exceptions as well. Those in charge of institutions made lists of their personnel or inmates, in some cases using initials only, in others, surnames with first initial. The lists usually appear at the end of the appropriate district. And finally, ships were listed according to where they were in port on census night.

Each enumerator wrote a description of his or her district. This is important information, often bypassed by genealogists. The account provides a detailed description of the area and may include names of small farms and businesses. The information here can be used with a large-scale map to precisely locate the home of an ancestor. In some situations, this information is essential when sorting out the boundaries of districts in towns and cities. Search problems occur because it may not be realized that a long road can cross through two or more districts, or that the census taker may go along a street, down side streets, cross the road, or come back another way. Descriptions help sort this out.

Next time you consult a census, take time to consider how it came into being. It might help your research, but it should also leave you amazed at what those early census takers accomplished.

Sherry Irvine, FSA (Scot) has been researching her British ancestry for over thirty years. She founded Interlink Bookshop and Genealogical Services in 1988, and she currently lectures in Canada and the United States and is a past vice president of the Association of Professional Genealogists. Sherry is the author of Your Scottish Ancestry: A Guide for North Americans and Your English Ancestry: A Guide for North Americans.