Northumberland is the most northern county in England. Lindisfarne is an island close offshore. The county town is Morpeth. Its finest church is Hexham Abbey. Historically Northumberland occupies a small part of the former Anglo-Saxon kingdom of Northumbria.
Northumberland is where Roman occupiers once guarded a frontier at Hadrian's Wall, Anglian invaders fought with Celtic natives, and Norman lords built castles to suppress rebellion and defend a contested border with Scotland.
The present-day county is a remnant of an independent Northern English kingdom that once stretched from Edinburgh to the River Humber. Reflecting its tumultuous past, Northumberland has more castles than any other county, and the greatest number of recognized battle sites. Once an economically important region that supplied much of the coal that powered the industrial revolution, Northumberland is now a rural county with a small and gradually shrinking population.
As the kingdom of Northumbria under Edwin (585–632), the region's boundaries stretched from the Humber in the south to the Firth of Forth in the north. The kingdom and county were named for the Humber.
The county is noted for its undeveloped landscape of high moorland, a favourite with landscape painters, and now largely protected as a National park. Northumberland is the most sparsely populated county in England, with only 62 people per square kilometre. This is mainly because the large cities of Newcastle upon Tyne and Tynemouth were joined to Gateshead and Sunderland in the metropolitan county of Tyne and Wear.