Capel Herbach is situated next to a small stream, some 70m south of the adjacent C road and immediately east of the grounds of an adjacent dwelling. The ruined chapel is said to be much the same in character as nearby (1.6km west) Capel Bigawdin (NPRN 303970), and the two are thought to be contemporary, possibly dating to the fourteenth century. According to Lewis's Topographical Dictionary of Wales, in 1844 there were two chapels of ease to St David's Chapel, LLanarthney. One was noted to be in ruins, and the other occupied by dissenters. Capel Herbach is thought to be one of these chapels of ease. Capel Herbach is also one of three chapels (the others being Capel Bigawdin and Capel Dyddgen (NPRN 303927)) described in Archaeologia Cambrensis as being in a straight line, within some three miles of one another, following the eastern side of the Gwendraeth Valley at its northen (or upper) end.

In 1894 the building was noted to be ivy-covered, with the west and most of the south walls remaining. Two or three feet of the bottom of the east wall were also in existence, but were obscured by poultry houses belonging to the occupiers of the adjacent small holding. The west door, a narrow window above, and the belfry were well preserved at this time. Measurements of the building are given as 37.5ft x 16ft. The height of the south wall is given as 13ft higher than the floor level, which was noted have been raised by surrounding debris. Measurements of the door are given as 5ft 10in height x 3ft width. Measurements of the window are given as 9 or 10in wide and 3ft 6in height. Several small openings were noted in the walls, one two or three feet from the north side of the alter. Its measurements are given as forty inched by twelve inches square, ending in a pointed arch at the top. A former resident remembered the existence of a water stoup, and a well in the floor, whose overflow exited through a spout to the south of the west door. The well had silted up by 1894, but the water, by this time having formed a channel under floor level, continued to exit through the spout in the west wall. The well, which reportedly comes from limestone, appears to have had healing properties, as people with sprains or broken bones continued to visit the chapel and hold their injured limbs under the spout.

The site was visited by RCAHMW staff in 1912, who noted that the west wall was still standing, within which was a plain pointed door with a trifoliated single lancet window above. Measurements of the door are given as 5ft 6in height x 3ft width. Measurements of the window are given as 3ft 6in x 1ft. A recess with a pointed arch was noted in the interior north-east corner. Its measurements are given as 3ft 6in x 14in. it was noted that sufferers of spasms continued to visit the well.

The chapel was surveyed in 1953, and the spring was reported still to flow from the west wall, into a tank or culvert, and thence into the adjacent stream. The chapel was excavated and rennovated in the 1970s by Carmarthenshire Antiquarian Society.

Sources include:
Kay, R.E, 1953, 'Herbach', R.E Kay notebooks, Series III Vol VII (June 1953-March 1954), 597-601
Tierney, H.C, 1894, 'Unexplored Ecclesiastical Ruins in Carmarthenshire', Archaeologia Cambrensis
'Stray notes on the Carmarthenshire report of the Royal Commission on Welsh Antiquaries', Transactions of the Carmarthenshire Antiquarian society, 1917-1918, P3
www.genuki.org.uk/big/wal/CMN/Llanarthney

N Vousden, RCAHMW, 29 August 2012