County Durham

County Durham, officially simply Durham (/ˈdʌrəm/), is a ceremonial county in North East England. The county borders Northumberland and Tyne and Wear to the north, the North Sea to the east, North Yorkshire to the south, and Cumbria to the west. The largest settlement is Darlington, and the county town is the city of Durham. The county has an area of and a population of 866,846. The latter is concentrated in the east; the south-east is part of the Teesside built-up area, which extends into North Yorkshire. After Darlington (92,363) the largest settlements are Hartlepool (88,855), Stockton-on-Tees (82,729), and Durham (48,069). The county contains three districts — Darlington, Hartlepool, and County Durham — and part of a fourth, Stockton-on-Tees. All four are unitary areas. The county historically included the part of Tyne and Wear south of the River Tyne and excluded the part of County Durham south of the Tees. The west of the county contains part of the North Pennines, which are an Area of Outstanding Natural Beauty. The hills are the source of the rivers Tees and Wear, which flow west and form the valleys of Teesdale and Weardale respectively. The east of County Durham is flatter, and characterised by rolling hills through which the rivers meander; the Tees forms the boundary with North Yorkshire in its lower reaches, while the Wear exits the county near Chester-le-Street in the north-east. The county's coast is a Site of Special Scientific Interest characterised by tall limestone and dolomite cliffs. What is now County Durham was on the border of Roman Britain, and contains survivals of this era at sites such as Binchester Roman Fort. In the Anglo-Saxon period the region was part of the Kingdom of Northumbria. In 995 the city of Durham was founded by monks seeking a place safe from Viking raids to house the relics of St Cuthbert. Durham Cathedral was rebuilt after the Norman Conquest, and together with Durham Castle is now a World Heritage Site. By the late Middle Ages the county was governed semi-independently by the bishops of Durham and was also a buffer zone between England and Scotland. County Durham became heavily industrialised in the nineteenth century, when many collieries opened on the Durham coalfield. The Stockton and Darlington Railway, the world's first public railway to use steam locomotives, opened in 1825.