[Go to England.]
When doing genealogical research, records will be organised by and make reference to various types of administrative units. Some knowledge of these can be useful to understand the records.
FamilySearch has a very useful map of English jurisdictions as they stood in 1851. This map is interactive, allowing the user to display of map of a selected type of jurisdiction, and to click on an area and see which of the other jurisdictions it belongs to, and the years that Anglican Church Records start.
Historic counties (pre-1974)
England was divided into about fifty counties, the highest traditional unit of subdivision in England. These boundaries remained roughly unchanged until reforms in 1974. Their use is preferred in genealogy to the Ceremonial Counties of post-1974.
Abbreviations (Champman codes)
From 1974 onwards, ceremonial counties have become an important unit of subdivision in England. England now has a two-tier system of counties and districts(sometimes boroughs or Royal Boroughs). These ceremonial counties correspond roughly to the old counties, with the exceptions that Manchester, Birmingham and London now have their own counties. These ceremonial counties do not necessarily have any administrative purposes today, for in many the County Council has been abolished and all local governance is now done by the districts.
The basic unit until the late nineteenth century in England was the parish. Church Records and Censuses were generally arranged by parish, and Registration Districts for Civil Registration and Poor Law Unions for poor relief were generally created by merging several parishes together. Parishes have now been abolished in many areas, but there is a growing trend of re-establishing parishes as the very lowest level of local government.
This wiki has articles for many parishes of England, as linked below;
Civil Registration is based on the Registration District. These usually covered multiple parishes merged together. When searching indexes of civil registration you will need to know what registration district the birth, marriage or death you are looking for occurred in.
Their boundaries changed frequently over the years. Fortunately the website GENUKI has a database of England Registration Districts that covers at least up to 1974.
See England Hundreds
The Hundred is a very old subdivision of a County used in some records, notably the 1841 Census.