The census has been conducted every ten years since 1801 and most recently in 2001. The first four censuses (1801-1831) were mainly statistical (that is, they were mainly headcounts and contained virtually no personal information).
The 1841 Census, conducted by the General Register Office, was the first to record the names of everyone in a household or institution. However, their relationship to the head of the household wasn’t noted, although sometimes this can be inferred from the occupation shown (e.g. servant). Those under the age of 15 had their proper ages listed, but for those who were older the ages were supposed to be rounded down to the nearest five years, although this rule was not strictly adhered to. Precise birthplaces were not given - at best the birthplace can be narrowed down to the county in which the person was living.
From 1851 onwards the census shows the exact age and relationship to the head of household for each individual; the place of birth was also listed, but with varying degrees of precision. Sometimes those who were born abroad have the annotation B.S. or British Subject.
The 1861 Census for England was taken on the night of 31 March 1861. Census returns were collected according to registration district. These returns were divided into sub-districts and assigned consecutive piece numbers for reference purposes.
The censuses are reasonably accurate. However, ages in particular are frequently shown incorrectly, though often the difference is only one year; in general the younger the individual the more accurate the age shown. Birthplaces often vary from one census to the next: a common error is to show the place where the census was taken as the birthplace, but most of the variations in birthplace can be accounted for by changes in geographical scale (for example, the nearest town being shown instead of the precise village, or a city being shown instead of the relevant suburb).
The censuses are also remarkably complete - though inevitably a small percentage of the population wasn’t recorded for one reason or another, and in some cases the records are missing or damaged (notably in 1861).
Because of World War II, there was no census in 1941. However, following the passage into law (on 5 September 1939) of the National Registration Act a population count was carried out on 29 September 1939, which was, in effect, a census.
The census is undertaken for the government by the Office for National Statistics (ONS) for policy and planning purposes, and statistical information is also made available in published reports and on the ONS's website. Public access to the census returns is restricted under the terms of the 100-year rule and the most recent returns made available to researchers are those of the 1901 Census.
All of the British censuses from 1841-1901 have been transcribed and indexed and are available online.
UK Census dates
| Year | Date | Notes |
|---|---|---|
| 1801 | 10 March | Details collected were mainly head-counts, with few still existing. |
| 1811 | 27 May | Details collected were mainly head-counts, with few still existing. |
| 1821 | 28 May | Details collected were mainly head-counts, with few still existing. |
| 1831 | 30 May | Details collected were mainly head-counts, with few still existing. |
| 1841 | 6 June | |
| 1851 | 30 March | |
| 1861 | 7 April | |
| 1871 | 2 April | |
| 1881 | 3 April | |
| 1891 | 5 April | |
| 1901 | 31 March | |
| 1911 | 2 April | |
| 1921 | 19 June | |
| 1931 | 26 April | Destroyed in World War II |
| 1939 | 29 September | National Registration Act 1939. No census in 1941 because of the Second World War. |
| 1951 | 8 April | |
| 1961 | 23 April | |
| 1971 | 25 April | |
| 1981 | 5 April | |
| 1991 | 21 April | |
| 2001 | 29 April |