Bordering Tyne and Wear, North Yorkshire and Northumberland, it forms part of the North East England region.
The structural change legislation in 2009, however, referred it to the county of County Durham. The former postal county was known as "County Durham" to distinguish it from the post town of Durham. Durham is the only English county name to be prefixed with "County" in common usage - a practice more predominant in Ireland.
There are a variety of industrial heritages present in County Durham ranging from mining and agriculture country wide to heavy railway industry in Stockton, Darlington and Shildon.
County Durham's economy was historically based on coal and iron mining. It centred round the development of the mining industry which, at its peak, employed almost the whole of the non-agricultural population. Consequently, County Durham has a significant number of villages that have grown around coal pitts.
However, trade unionism developed in County Durham through the medium of the Durham Miners Gala, an event that first took place in 1871. The decline of coal mining lead to the closure of many pitts. Many miners within County Durham took part in the miners strikes of 1984/5. Presently no deep-coal mines exist in County Durham and numbers attending the Miners' Gala have declined significantly over the period, although recent years have seen numbers increase, and more banners return to the Gala as former collieries restore former banners.
Among other early industries, lead-mining was carried on in the western part of County Durham, and mustard was extensively cultivated. Gateshead had a significant tanning trade and shipbuilding was undertaken in County Durham at Sunderland, which became the largest shipbuilding town in the world - developing a third of Britain's tonnage.
Interesting places to visit in County Durham include the National Heritage Site Durham Cathedral and castle. The University of Durham can be found in Durham city.