Ynysymaengwyn Estate (Wales) -- Archives.
- Corporate body
Ynysymaengwyn Estate (Wales) -- Archives.
Ynys-hir estate (Ceredigion, Wales) -- History.
Ynyshir and Wattstown Free Church Council.
Ynyscedwyn Iron, Steel & Coal Company.
Ynysau Gate (Cynwyl Gaeo, Wales : Dwelling)
Ynisarwed Resolven Colliery Company.
Ynisarwed Colliery (Cadoxton-juxta-Neath, Wales).
Ymddiriedaeth Ysgolion Cymraeg
YMCA. Liverpool (Welsh Branch) -- History
Yew Tree Cottage (Kerry, Wales)
Yes for Wales (Organisation) -- Archives.
Yes for Wales 1979 Devolution Referendum Campaign