RHONDDA, an urban district of Glamorganshire, South. Wales, 12 rrl. long by about 4i m. across at its widest part, com prising two main valleys, named after their respective rivers, Rhondda Fawr and Rhondda Fach. The valleys are deeply incised in the coal measures of the South Wales geological basin and their lateral boundaries are formed by hills varying from 56o ft. near Trehafod to 1,34o ft. on the north-east of Maerdy in the Rhondda Fach and 1,742 ft. on the south-west of Treherbert in the main valley. The upper end of the latter valley culminates in Carn Moesen (1,95o feet). The two valleys are separated by the ridge of Cefn-rhondda, which ranges from 600 ft. above Porth to 1,690 ft. near the upper end of the district. There are tributary valleys of which Cwmparc, Clydach vale, and Cymmer are the chief.
The Rhondda valley is the centre of the eastern division of the South Wales coalfield. The development of the Rhondda coalfield was later than that of the northern sections of the South Wales area, where coal was worked early for iron smelting. It was the unsurpassed steam-raising properties of the Rhondda coal that made the region famous after the period 186o-65. With the great demands made for steam-coal by the ever increasing railway traf fic, steam-ship service and navies of the last half of the 19th century, the Rhondda from being a purely pastoral upland region was transformed into a densely-populated industrial valley. No thought was given to the elongated straggling settlements that grew up or to the development of by-products to ensure employ ment in the region when the coal exporting phase would pass away. Furthermore, in the elongated settlements (the whole of
the Rhondda valleys from Blaen-rhondda and Maerdy to Porth and Pontypridd is now one long winding street) the absence of central buildings, public squares, and shopping centres has counted against the development of a strong civic sense : a feature that has become more acute in an industrial region such as this, with no tradition of previous settlement and with a population almost all engaged on one kind of work for masters living usually far away.
The population was estimated at 23,95o in 1871, but it reached 55,632 in 1881, and 113,735 in 1901. In 1931 it reached 141.344. Area of Urban district 23,886 acres. In 1877, the ancient parish of Ystradyfodwg (excepting the township of Rhigos) was formed into an urban district. In 1879, portions of the parishes of Llan wonno and Llantrisant were added to the urban area, the whole being consolidated in 1894 into one civil parish. In 1897, the name of the urban district was changed into Rhondda.
With the development of the coal exporting trade a number of small railway companies connected these valleys with Cardiff on the one hand and via the Blaengwynfi tunnel with Port Talbot and Swansea on the other hand. All these smaller lines are now amalgamated with the G.W. railway. The lack of demand for steam coal, trade depression, and changes in the world-market have seriously affected the region since 1921. Depopulation, un employment and poverty are very marked.