Rhondda Cynon Taff on Wikipedia.

Aberaman.
Abercwmboi, Bethesda Welsh Baptist Chapel (1864, Grade II listed). Life in the Nations Church (Charismatic), originally Bethlehem Welsh Independent Chapel. Abercwmboi Christian Centre, in the former Abercwmboi Miners's Institute. All © Gerard Charmley (2010).
Abercynon.
Aberdare.
Abernant, St. Matthew (CIW). Bethel Baptist Church (1856). Both © Gerard Charmley.

Beddau, St. Michael (CiW). Link. Beddau Community Church (Elim Pentecostal). Link. © Gervase N. E. Charmley.
Blaenllechau, the former St. Thomas (CiW), now closed. Nazareth Welsh Baptist Church (1901). Carmel Chapel (Independent Evangelical), originally Calvinistic Methodist (1868). Link. All © Gervase N. E. Charmley.
Blaenrhondda, Wesleyan Methodist Church (1894). © Gervase N. E. Charmley.
Bryncae, the former Bethany Presbyterian Church. © Gervase N. E. Charmley.
Bryncynon, the former All Saints (CiW), now a healthy-living centre. © Gerard Charmley.
Brynna, St. Peter (CiW); built in 1832, it replaced the old church of Peterston-super-Montem (now ruined - see below). Methodist Church, built as a United Methodist Church. Previously, the congregation (Bible Christian) met in a Tin Chapel following their establishment in 1900. The Bible Christians were one of a number of small groups who formed  the United Methodists in 1907, and the present building dates from 1908. Both © Gervase N. E. Charmley.
Brynsadler, the former Capel Sion (Calvinistic Methodist, 1863), now a private residence. © Gervase N. E. Charmley.

Castellau, Congregational Church. © Gervase N. E. Charmley.
Cefnpennar, Parish Church. Cefnpennar Baptist Church (closed). Both © Gerard Charmley (2010).
Church Village, St. Illtyd, the parish church. The tower dates from 1636. Salem Baptist Church. Another view. Bethel Baptist Church. All © Gervase N. E. Charmley.
Cilfynydd, St. Luke the Evangelist (CiW). Beulah Baptist Church. The former Moriah Welsh Independent Chapel (closed). All © Gerard Charmley (2010).
Clydach Vale.
Codepenmaen, Pontypridd - see Pontypridd.
Cwmaman, Seion Welsh Baptist Chapel, and another view. The former Bethel Primitive Methodist Church (now flats). Moriahaman Welsh Independent Chapel. The former Trinity English Baptist Church, now a private residence. All © Gerard Charmley (2010).
Cwmbach, St. Mary Magdalene (CiW). Link. Cornerstone Church (Pentecostal), formerly Ebenezer Calvinistic Methodist Chapel. Link. The former Penuel Baptist Church, now a private residence. All © Gerard Charmley.
Cwmparc, St. George (CiW). Bethel Baptist Church (1873). Park Calvinistic Methodist Church. All © Gervase N. E. Charmley.
Cymmer, Porth - see Porth.

Edmondstown, Capel Cenhadol Y Graig. Dinas Mission (CiW). Link. Both © Gervase N. E. Charmley.
Efail Isaf, Capel Y Tabernacle (Welsh Independent). Another view. Both © Gervase N. E. Charmley. Link (Welsh), (English).

Ferndale.

Gelli, Mount Zion Pentecostal Church. Bronllwyn Mission Methodist Church was originally Gospel Mission (1925). Both © Gervase N. E. Charmley.
Glyntaff, St. Mary (CiW). Cemetery Chapel. Both © Gerard Charmley.
Godreaman, the former Bethany English Congregational Church. now flats. Gwawr Bilingual Baptist Chapel, originally Hebron Calvinistic Methodist Chapel. The original Gwawr Chapel was in Aberaman, and is now demolished. The former Nodffa Welsh Independent Chapel, now flats. The inscribed stone has the date 1800. All © Gerard Charmley (2010).
Graig, Pontypridd - see Pontypridd.
Groes-faen, St. David. Babel Calvinistic Chapel (1866). Both © Gervase N. E. Charmley.

Hirwaun.
Hopkinstown, St. David. Capel Rhondda Baptist Chapel (1852). Another view. Gervase advises that the hymn tune "Cwm Rhondda" was first sung here in 1907. All © Gervase N. E. Charmley.

Llanharan, St. Julius and St. Aaron. Another view. Carmel Baptist Church dates from 1901, but at some point has had a new front added. Link. The former Bethlehem Independent Chapel was founded in 1790, the present building dating from 1833, restored in 1894, and is currently (2009) being converted into a house. The former Wesleyan Methodist chapel closed in 2001. All © Gervase N. E. Charmley.
Llanharry, St. Illtyd (CiW). Link. Peniel Independent Chapel was built in 1825, with modification and restoration being carried out in 1850 and 1915. Another view. All © Gervase N. E. Charmley.
Llanilid, St. Ilid and St. Curig. © Gerard Charmley (2011). Link (near bottom of page).
Llantrisant.
Llantwit Fadre, the now-derelict Trinity Forward Movement Hall (Presbyterian, 1913). © Gervase N. E. Charmley.
Llanwonno (CiW), St. Gwynno. Another view. ST 0301 9561. Both © David Rowlands. Link. Coflein. Grade II listed. A graveslab is also listed, as grade II.
Llwydcoed, St. James (CiW). Nebo Welsh Independent Church is closed. Both © Gerard Charmley.
Llwynypia, St. Cynon (CiW). A glimpse of Salem Independent Chapel. Both © Gervase N. E. Charmley.

Maerdy, All Saints (CiW). Sion Baptist Church (1882). Former Chapel. Thanks to David Bolton for advising that it was Carmel Baptist Chapel. All © Gervase N. E. Charmley.
Miskin (Pontyclun), St. David. It dates from 1907 and replaced an Iron Church. Link. All Hallows (R.C.). Both © Gervase N. E. Charmley. The former Calvinistic Methodist Chapel. © Gerard Charmley (2011).
Miskin (north of Abercynon), St. John the Baptist. The former St. Teilo. My appreciation to Janet Gimber for providing the identification, and this confirmatory link. Miskin Methodist Church. Miskin Baptist Church. Kingdom Hall of Jehovah's Witnesses, previously Canaan Congregational Church. All © Gerard Charmley.
Mountain Ash.

Nantgarw, the former St. Mary (CiW) closed in 1983, and is now a private residence. Link. Gospel Hall. Both © Gerard Charmley.
Newtown, Zion Methodist Church (originally Primitive Methodist). © Gerard Charmley (2010).
Norton Bridge, Methodist Church. © Gerard Charmley (2010).

Penderyn, St. Cynog (CiW). Another view. Link. Soar Methodist Chapel (1860 - the date-stone also mentions 1912). Siloam Baptist Chapel, bult 1823 and re-built 1837. All © Peter Morgan (2011).
Penrhiwceiber, St. Winifred (CiW). The former Bethel Wesleyan Chapel (1894), now a builders mercHampshire. Carmel Baptist Chapel (1880). Hope Methodist Church, originally Primitive Methodist (1907). All © Gerard Charmley.
Pentre.
Penygraig, St. Barnabas. The chancel arch in the end wall shows that a chancel was planned, but never built. Another view. Many churches in Rhondda were founded as Iron Churches, but most were demolished when a stone church was built. Here it survives, though in a sorry state. The former Pisgah Calvinistic Methodist Church, now a funeral chapel. The former Soar Baptist Chapel. All © Gervase N. E. Charmley.
Peterston Super Montem, the ruined and remote church of St. Peter (also see Brynna, above). Originally dating from C12, it was re-built in the 17th century, and abandoned in the 19th. Two further views - 1, 2. All © Gervase N. E. Charmley.
Pontyclun.
Ponygwaith, the former Hermon Welsh Baptist Church (1881). Soar Calvinistic Methodist Church. Both © Gervase N. E. Charmley.
Pontypridd.
Porth.
Pwllgwaun, Pontypridd - see Pontypridd.

Rhydyfelin, St. Luke (CiW). Methodist Church. The former Bethlehem Baptist Chapel, now a private residence. All © Gerard Charmley.
Robertstown, Salem Welsh Independent Chapel. Probable former church - can you name it? Thanks to a fine piece of detective work, Janet Gimber has shown that this was originally St. John the Evangelist (CiW), but it is now Aberdare Islamic Centre. (link). Both © Gerard Charmley.

Talygarn, St. Anne. The ruins of the old church, which was originally a private chapel for Talygarn Manor. Both © Gervase N. E. Charmley.
Ton Pentre.
Tonypandy.
Tonyrefail.
Trealaw, All Saints (CiW). The former Carmel English Baptist Chapel (1904). Trealaw Christian Fellowship Centre (Apostolic). Link. Elim Pentecostal Church. originally the vestry to the now-demolished Bethlehem Baptist Chapel. The former Tabernacle Welsh Independent Church. All © Gervase N. E. Charmley.
Trebanog, English Congregational Church (1881), a "Tin Tabernacle", as is the following church. Mt. Zion English Baptist Church. Another view. All © Gervase N. E. Charmley.
Trecynon.
Treferig, the scant remains of a Quaker Meeting House, dating originally from the 17th century. © Gervase N. E. Charmley.
Treforest.
Trehafod, St. Barnabas (CiW). The former Bethesda Baptist Church. Both © Gervase N. E. Charmley.
Treherbert.
Treorchy.
Tylorstown, Trinity Church (CiW). Tylorstown Methodist Church. Capel Zion (Calvinistic Methodist). All © Gervase N. E. Charmley.

Wattstown, Calfaria Welsh Baptist Church (1894). The former Carmel Welsh Independent Church (1906). The charmless Bethel Free Mission. All © Gervase N. E. Charmley.
Williamstown, St. Illtyd. Link. Sion Welsh Wesleyan Methodist Chapel (1878). The former Nazareth Calvinistic Methodist Church. Bethabara Baptist Church. The former English Wesleyan Chapel, now a youth club - thanks to David Bolton for the ID. All © Gervase N. E. Charmley.

Ynyshir, St. Anne (CiW). Ainon Welsh Baptist Church (1886). Moriah Calvinistic Methodist Church (1909; Gervase advises that it looks closed). Bethany English Baptist Church. Link. Welsh Wesleyan Methodist Church. Saron Welsh Independent Church. All © Gervase N. E. Charmley.
Ynysboeth, the former Carmel English Methodist Church (virtually unrecognisable, advises Gerard). © Gerard Charmley.
Ynyswen, Ainon Welsh Baptist Chapel (1899). Providence English Baptist Chapel (1910), a surviving "Tin Tabernacle". Another view. The derelict Methodist Church. All © Gervase N. E. Charmley.
Ynysybwl.
Ystrad.