If you're interested, Wye comes from the name of the river, which means either to wander, or crooked hills. Either seem relevant given the strange way that the river wye goes from wide, slow meandering bends across floodplains into rapids through steep crooked valleys (as opposed to most rivers that start in mountains and end in floodplains.)

Monmouth is at the mouth of the river Monnow, a tributary of the Wye.