[2] By the early 15th century, Grosmont had become a large and important settlement - only Abergavenny and Carmarthen were larger in the whole of South Wales.

Any structures that may have existed at that time, including the market hall, were destroyed when an army of 8,000 followers of the Welsh Prince, Owain Glyndŵr, burnt the town to the ground during the Battle of Grosment in 1405.

It was originally arcaded and open on all sides, to allow markets to be held, with an assembly room for the borough council on the first floor.

[7] The town hall was the venue for the annual mayor-making ceremony,[8] until the borough was abolished and replaced by a local parish council in 1857.

[9][10] Henry Somerset, 9th Duke of Beaufort offered the town hall to Grosmont Parish Council in May 1902.