The wapentake is named after Northallerton (historically "Allerton"), its chief town. The wapentake was once vested in the Bishop of Durham as a liberty, and remained an ecclesiastical peculiar belonging to Durham until the 19th century.
In 2011, Allertonshire had a population of 22,265.
The wapentake includes the ancient parishes of:
- Great Smeaton (Hornby township, part)*
- Hutton Conyers (ex. par.)
- Kirby Sigston
- Kirklington (Howgrave township)†
- North Otterington (except Thornton-le-Moor)‡
- Pickhill (Holme township)†
- Sessay (part)§
- Sockburn (townships of Girsby and Over Dinsdale)‖
- Wath (Norton Conyers township)†
- West Rounton
*: Remainder of Hornby in Langbaurgh Wapentake; Great Smeaton township in East Gilling.
†: Remainder in Hallikeld wapentake.
‡: In Birdforth Wapentake.
§: Part of Hutton Sessay in Birdforth wapentake.
‖: Remainder in County Durham.
Wapentakes of Yorkshire
East Riding: Buckrose • Dickering • Harthill • Holderness • Howdenshire • Ouse and Derwent • North Riding: Allertonshire • Birdforth • Bulmer • East Gilling • Hallikeld • Hang East • Hang West • Langbaurgh • Pickering Lythe • Ryedale • West Gilling • Whitby Strand • West Riding: Agbrigg and Morley (Agbrigg, Morley) • Ainsty • Barkston Ash • Claro • Osgoldcross • Skyrack • Staincliffe and Ewcross (Staincliffe, Ewcross) • Staincross • Strafforth and Tickhill