Just as Edward was inclined to leave the far North to the Nevilles, so he was inclined to leave Wales to his supporters there, of whom the most remarkable was Sir William Herbert. (It appears that originally Edward planned to campaign in Wales in the summer of 1461, but in the event he never got further than Ludlow and returned to Westminster to hold his first Parliament.)
Herbert was a Welshman, and was to be the first of that nation (barring King Henry VI's Tudor half-brothers, who were a bit of a special case) to be granted an earldom. He undoubtedly earned this honour, and was to pay a terrible price for it in the fullness of time. Knighted by King Henry in 1449, William Herbert had fought in the French wars under Somerset, but despite this - or maybe because of it - became a strong Yorkist supporter. Edward was swift to appoint him to his Privy Council and in May 1461 made him Chamberlain and Chief Justice of South Wales.
The main Lancastrian threat in Wales was organised by Jasper Tudor, Earl of Pembroke, who had of course fought at Mortimer's Cross and was to continue to be a thorn in the side of the Yorkist dynasty all the way to Bosworth. Jasper was undoubtedly a warrior of some ability and he appears to have enjoyed some popularity in Wales - at least he was always able to find some Welshmen willing to fight for him. (It is a little odd that Wales was as pro-Lancastrian as it was, given the treatment handed out to that country by Henry IV and his son, but there you are.)
Herbert captured the formidable castle of Pembroke on 30 September, then defeated Tudor, Exeter and the main force of Welsh Lancastrians at Twt Hill near Caernarfon on 16 October. On 4 November Herbert was rewarded with a barony, as Lord Herbert, and granted the castle, town and lordship of Pembroke. The promotion was obviously fully merited.
Denbigh and Carreg Cennan castles fell to the Yorkists in early 1462, but Harlech still held out, and was to continue to do so until 1469. One must assume that it was so remote that King Edward did not see its capture as a priority.