In 1085 William the Conqueror ordered that a survey should be carried out across his kingdom to discover who owned which parts and what it was worth. The survey took place in 1086 and the results were recorded in what, since the 12th century, has become known as the Domesday Book. Starting with the king himself, for each landholder within a county there is a list of their estates or manors; and, for each manor, there is a summary of the resources of the manor, the amount of annual rent that was collected by the lord of the manor both in 1066 and in 1086, together with the taxable value. Hartford was listed in the Domesday Book in the Hundred of Hurstingstone in Huntingdonshire; the name of the settlement was written as Hereforde in the Domesday Book. In 1086 there was just one manor at Hartford; the annual rent paid to the lord of the manor in 1066 had been £24 and the rent had fallen to £15 in 1086. The Domesday Book does not explicitly detail the population of a place but it records that there were 34 households at Hartford. There is no consensus about the average size of a household at that time; estimates range from 3.5 to 5.0 people per household. Using these figures then an estimate of the population of Hartford in 1086 is that it was within the range of 119 and 170 people. The Domesday Book uses a number of units of measure for areas of land that are now unfamiliar terms, such as hides and ploughlands. In different parts of the country, these were terms for the area of land that a team of eight oxen could plough in a single season and are equivalent to ; this was the amount of land that was considered to be sufficient to support a single family. By 1086, the hide had become a unit of tax assessment rather than an actual land area; a hide was the amount of land that could be assessed as £1 for tax purposes. The survey records that there were twelve ploughlands at Hartford in 1086 and that there was the capacity for a further five ploughlands. In addition to the arable land, there was of meadows, of woodland and two water mills at Hartford. The tax assessment in the Domesday Book was known as geld or danegeld and was a type of land-tax based on the hide or ploughland. It was originally a way of collecting a tribute to pay off the Danes when they attacked England, and was only levied when necessary. Following the Norman Conquest, the geld was used to raise money for the King and to pay for continental wars; by 1130, the geld was being collected annually. Having determined the value of a manor's land and other assets, a tax of so many shillings and pence per pound of value would be levied on the land holder. While this was typically two shillings in the pound the amount did vary; for example, in 1084 it was as high as six shillings in the pound. For the manor at Hartford the total tax assessed was 15 geld. By 1086 there were two churches and a priest at Hartford.
Demography
Population
In the period 1801 to 1901 the population of Hartford was recorded every ten years by the UK census. During this time the population was in the range of 283 and 452. From 1901, a census was taken every ten years with the exception of 1941.
