There were no official Enumeration Districts created for the 2011 Census.
Households in England and Wales received their census questionnaire through the post and returned them by post or online.
Only communal establishments, for example, care homes, and special groups (such as travellers) had their census questionnaires hand delivered. Individuals within communal establishments also had the option of completing their questionnaire online following the same process as that used by households.
Enumeration Districts (EDs) were used for data collection for the 2001 Census. England and Wales had 116,895 EDs, the majority of which were different from their 1991 equivalents, with an average size close to 200 households (450 people).
Scotland had 6,987 EDs at an average size of 328 households (730 people) and Northern Ireland had 2,591 EDs at an average size of 260 households (650 people).
In addition there were Special Enumeration Districts (SEDs) for communal establishments with the capacity to house over 100 people. SEDs included prisons, hospitals, nursing homes, halls of residence, large hotels and military bases.
Enumeration Districts sometimes straddled 2001 administrative boundaries and were deemed unsuitable for data output and were used for data collection only.
Output Areas were introduced for data output.
1991 Enumeration Districts were used for both data collection and output. Their size and shape was primarily determined by the requirements of data collection but they fitted the administrative boundaries current at the time.