 Nelson was originally called Ffos-y-Gerddinen ("ditch of the rowan"), a relatively flat piece of land at the southern extremity of the Taff Bargoed Valley to the south of the hamlet of Llancaiach.It existed on a drovers trail from the South Wales coast towards Merthyr Tydfil and onwards to Brecon and Mid Wales, where an enterprising man built a coaching inn that he called Nelson, possibly after Admiral Lord Nelson and his victory at the Battle of Trafalgar.Had it not been for the development of the South Wales coalfield, Nelson would have remained just a coaching inn surrounded by fields.