It covers an area of more than 1,050 square kilometres (410 sq mi) between the Scottish border in the north to just south of Hadrian's Wall.

Of the thirteen National Parks in England and Wales, Northumberland is the most remote from large urban areas, the least populated, and the least visited.

Further south, the hills give way to areas of rolling moorland, some of which have been covered by forestry plantations to form Kielder Forest.

The 10,000-year history of human habitation of the region is explored through the many archaeological sites, ranging from prehistoric monuments and Roman remains to Pele towers, constructed as a defence against invading Scots and Border Reivers.

Northumberland means "country north of the River Humber" and is related to the name "Northumbria", referring to the former Anglo-Saxon kingdom which once covered much of Northern England.