Reginald's Tower is located at the heart of Waterford City at the eastern end of the city quay.  The first tower on the site was built by Vikings after 914 and formed the apex of the triangular settlement, an area known to this day as the Viking Triangle. 

The Tower is an important remnant of its medieval urban defence system and remain in continuous use, in a different purpose, for over 800 years.  It was rebuilt by the Anglo Normans in the 12th century the top two floors were added in the 15th century.  Until about 1700 the tower was the strongpoint of the medieval defensive walls that enclosed the city. The tower now houses an exhibition on Viking Waterford and is managed by the Office of Public Works.