The famous Domesday book, a manuscript record of the "Great Survey" of much of England and parts of Wales, was commissioned in 1085 and completed in 1086 by order of William I, or "William the Conqueror". Six great Domesday circuits were conducted, with Bedfordshire, Buckinghamshire, Cambridgeshire, Hertfordshire, Middlesex being included in Circuit Three.

The Hundred Rolls are a census of England and parts of what is now Wales taken in the late thirteenth century. Often considered an attempt to produce a second Domesday Book, they are named after the hundreds by which most returns were recorded. The Rolls include a survey of royal privileges taken in 1255, and the better known surveys of liberties and land ownership, taken in 1274–5 and 1279–80, respectively. The two main enquiries were commissioned by Edward I of England to record the adult population for judicial and taxation purposes.

No actual headcount in Britain was conducted until the Posse Comitatus ("force of the County") in February 1798, the powers-that-be having concerns that they would have difficulty raising up a civil force should France invade England. They therefore directed that returns be prepared of men that could serve in the event of riot, insurrection or invasion. In addition, the number of horses, wagons and carts were surveyed. Buckinghamshire is the only county for which a complete copy of the Posse Comitatus exists.

UK censuses were initially conducted partly to ascertain the number of men able to fight in the Napoleonic Wars, and partly over population concerns stemming from the 1798 work "An Essay on the Principle of Population" by Reverend Thomas Robert Malthus. The census is a head count of everyone in the country on a given day.

A census has been taken in England and Wales, and separately for Scotland, every ten years since 1801, with the exception of 1941. The first four censuses, 1801 through 1831, were taken strictly for statistical purposes for the Overseers of the Poor and substantial households. The first census listing people by name was taken in 1841. Census records are generally released 100 years after they were taken.

Census dates :-

• 1841 - 6th. June
• 1851 - 30th. March
• 1861 - 7th. April
• 1871 - 2nd. April
• 1881 - 3rd. April
• 1891 - 5th. April
• 1901 - 31st. March
• 1911 - 2nd. April
• 1921 - 19th. June