It extends from near Caergwrle in the north, southwards through Wrexham, Ruabon and Rhosllannerchrugog to Chirk in the south.
Beyond Caergwrle the coal-bearing strata continue northwards as the Flintshire Coalfield.
[1] The shallower parts of the Denbighshire Coalfield were worked extensively in the early nineteenth century, most of the coal being used in the iron industry.
In the mid-nineteenth century, much deeper pits were established and a network of railways was built in the Wrexham area to transport the coal.
Prior to this time, as many as 38 collieries had been in operation across the area, with a peak output in excess of 2.6 million tons, and giving employment at the height of production to some 12,000 men.