So named because the family of Frederick Harry Lewis, owner of Nettlefield House, originated from Radnorshire in Wales. We are grateful to Judith Acheson for providing us with this information. F. H. Lewis is listed as a "country resident" at Nettlefield, Ballymacarret in the BPU Directory, 1861.
Radnor Street now runs from Woodstock Road to Nettlefield School.
Radnor Street had previously been called Louise Street.