Hengoed hamlet is in the south-east of the parish, and covers the area of the parish between Nant Cylla and the Rhymney river. The main communities in this hamlet today are Bargoed, Gilfach, Pen-pedair-heol, Tir-y-berth, Cefn Hengoed, Hengoed and Ystrad-Mynach. In the tithe schedule of 1841 there were 26 farms of between 8 and 270 acres. and a wool mill (pandy).
Its boundaries in 1750 are given as “it begins where Bargod River comes to the River Rumney by Aberbargode Bridge then along the River Rumney till it comes to the entrans of Killa brook to it by Ystrad Manerch then along Killa brook upwards till it comes to the high way that leadeth from Pen yr Hewl Ddu to Pen y Brin Ore to a white thorn bush that standeth in the hedge of Pen y Garreg farm and the stone on the common between the high way and the said hedge then along that hedge between Brin Coch and Pen y Garreg farms till it comes to nant Goch then along nant Goch downwards to pont Cradock then along the River Bargod to Aberbargod Bridge aforesaid”.
Although its population doubled between 1831 and 1841, there was only a slight increase betwwen 1841 and 1871. The population in each sucessive census is shown below. By 1881 population was no longer recorded by hamlet as their function had all but disappeared.
The farms as recorded in the 1841 tithe schedule are shown below. The tithe value has been converted to modern pounds/pence; it gives an indication of the relative values of the farms in 1841
** Dan y Pentre, in Cefn Hamlet, and Rhos y Bedw, in Hengoed Hamlet, were recorded as one 78 acre farm. Although the two farms are close they do not share a boundary.