Caerphilly County Borough (Bwrdeistref Sirol Caerffili) is a county borough in the south-east of Wales. It is governed by Caerphilly County Borough Council. Its main and largest town is Caerphilly. Other towns in the county borough are Bedwas, Risca, Ystrad Mynach, Newbridge, Blackwood, Bargoed, New Tredegar and Rhymney. Caerphilly County Borough is in southeast Wales and straddles the border between the historic counties of Glamorgan and Monmouthshire. It is bordered by Cardiff to the southwest, Newport to the southeast, Torfaen to the east, Blaenau Gwent to the northeast, Powys to the north, Merthyr Tydfil to the northwest and Rhondda Cynon Taf to the west. The northern part of the borough is formed by the broad expanse of the Rhymney Valley. The Rhymney River rises in the hills in the north and flows southwards for about thirty miles, looping round to the east just to the north of Caerphilly before reaching the Bristol Channel. Some of the larger towns are Bedwas, Risca, Ystrad Mynach, Newbridge, Blackwood, Bargoed, New Tredegar and Rhymney. The valley also includes the communities of Abertysswg, Fochriw, Pontlottyn, Tir-Phil, Brithdir, New Tredegar, Aberbargoed, Rhymney and Ystrad Mynach, and the towns of Bargoed and Caerphilly. Located on the edge of the South Wales Coalfield this area was sparsely populated with livestock husbandry being the main occupation. Farmers in their remote farmhouses on the windswept pastures might dig themselves some bucketfuls of coal for their hearth. Things began to change with the development of the iron industry, the start of the Industrial Revolution. In 1752, a 99-year lease was granted for a parcel of land in the Rhymney Valley which gave the lessees the right to mine coal and iron ore. Other such transactions followed, pitshafts were dug and the coal industry developed. By the beginning of the twentieth century, there were forty coalmines in the valley. One of the pits sunk in the late nineteenth century was the Elliot Colliery.