The Suir played a critical and unique role in the colonisation the country, first by the Vikings in the 9th century, and a few centuries later by the Normans, who from their strongholds in riverine cities such as Waterford were to change the face of Ireland. The river continued to play a major role in the history of the country in every century since: more English monarchs entered or left Ireland by way of the Suir and Waterford than by any other route.

The coming of the railways and modern road transport from the 19th century onwards moved economic emphasis away from rivers. The importance of the Suir as a water supply, as a main trading route connecting the hinterland with the seaport of Waterford, as an abundant source of fish, and as a source of waterpower is now a thing of the past, and in places its waters and banks have merged into the surrounding landscape, overgrown and almost forgotten.

Along these stretches, relatively undeveloped and undisturbed by man, the flora and fauna of our increasingly intensely cultivated countryside have found asylum; species survive and thrive that are no longer common elsewhere.

The sheer abundance of extant evidence of the Suir's former importance is remarkable: the river valley has an impressive density of prehistoric monuments, earthworks, castles, abbeys and ruined churches, all quietly co-existing today with the 21st century agricultural busyness of some of the finest farmland in Ireland.