Northumberland, England's northernmost county, is a land where Roman occupiers once guarded a walled frontier, 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 vestige of an independent kingdom that once stretched from Edinburgh to the Humber, hence its name, meaning literally 'north of the Humber'. Reflecting its tumultuous past, Northumberland has more castles than any other county in England, and the greatest number of recognised battle sites. Once an economically important region that supplied much of the coal that powered the industrial revolution, Northumberland is now a primarily rural county with a small and gradually shrinking population. Source: Wikipedia (en)