In 1868, the parish of Ystradyfodwg contained the following places:
"YSTRAD DYFODWG, a parish in the hundred of Miskin, county Glamorgan, 10 miles S.W. of Merthyr Tydfil. It is situated near the source of the Rontha, a branch of the river. Taff, and includes the ecclesiastical district and village of Clydach, and the hamlets of Home, Middle, and Rhigos. The village occupies a secluded spot in a mountain valley, which forms part of the great coal basin flanked on either side by ranges of hills rising to an elevation of 1,859 feet, and forming an amphitheatre of mountain. In the vale are several farms, chiefly the property of the Marquess of Bute, who owns almost the whole valley. The mountain streams here form several falls as they rush down to the Taff. The inhabitants are principally employed in the Dinas coal mines. The living is a perpetual curacy in the diocese of Llandaff; value £90, in the patronage of the Vicar of Llantrisant. The church is dedicated to St. Tyvodwg. There are several Dissenting chapels."
"CLYDACH, a hamlet in the parish of Ystrad-dyfodwg, hundred of Miskin, in the county of Glamorgan, South Wales, 9 miles N.W. of Llantrissant."
"HOME, a hamlet in the parish of Ystrad dyfodwg, hundred of Miskin, county Glamorgan, 6 miles S. of Merthyr-Tydfil."
"MIDDLE, a hamlet in the parish of Ystrad dyfodwg, hundred of Miskin, county Glamorgan, 8 miles S.W. of Merthyr-Tydfil."
"RHIGOS, a hamlet in the parish of Ystrad-dyfodwg, hundred of Miskin, county Glamorgan, 9 miles S.W. of Merthyr-Tydfil. The inhabitants are chiefly engaged in the Hirwaun ironworks."