Form B1, which was known as the House and Building Return, was completed by the enumerator and summarised the following administrative information for the street or townland, or part thereof: It then summarised the following information pertaining to the houses and families of the street or townland.

Form N, the Enumerator's Abstract for a Townland or Street, recorded the enumerator's name, the same administrative information as listed for Form B1, the properties and which were inhabited, and the numbers of families, males, and females, and persons of each religious denomination.

*Note: The County Borough of Belfast, established in 1888, straddled the border between Down and Antrim.

The borough of Belfast had 15 wards, three of which - Ormeau, Pottinger and Victoria - were south of the Lagan and have been included as part of County Down's population.

The returns are arranged by townland for rural areas and by street in cities, and it is necessary to know the townland or street where a person lived and its corresponding district electoral division to find the record of a particular person of interest.