The surname Northwood is of English origin and is a locational name derived from villages bearing the same designation in the British Isles.
Its etymology is plain. The components are the Old English words norð, meaning north, and wudu, meaning wood. The surname therefore identified an individual who lived near or in a forest situated to the north of a main settlement, or who resided in a place called Northwood or Norwood.
Recorded instances of the name appear in early royal documents. In the Pipe Rolls of Devonshire issued in 1176 during the reign of Henry II a person named Painot de Norwude is listed. Subsequent records include Mauger de Northwode in the Bedfordshire Hundred Rolls of 1273, William and David Bynorthewode, noted in the Devonshire rolls of 1330 as living north of a wood now associated with Northwood Farm near Okehampton, and Edmunde Northwoode, a student at Oxford University in 1592.
Several orthographic variations have been preserved in the historical record. The surname has been spelled as Norwood, Northward, Northwode, Nothwood, Norwud, Noorthwood, and Nortwood, among others. Such differences arise from the lack of standardised spelling in medieval clerical records and from changes in pronunciation over time.
In terms of distribution, the name remains most common in the United Kingdom. Census data show concentrations in the London area, the South East of England—including county towns such as Oxford and Windsor in Berkshire—and in the North West as well, notably Lancashire, Cumbria and Merseyside. The surname can also be found in Eastern Scotland, particularly Aberdeenshire. Historic migration has spread the name beyond the United Kingdom: it is recorded in various European countries, with significant communities in the United States, especially in New Jersey, Massachusetts, New York and Pennsylvania, and to a lesser extent in California, the Midwest, Texas, Florida and parts of the Sun Belt.
The continued use of Northwood and its variants reflects a long-standing tradition of using place-based surnames to denote geographical origin, a practice that predates the introduction of fixed street addresses and postal codes.