If your ancestors worked in the heavy industry in England or America’s urban jungles, then you might find they learned their trade in South Wales. During and after the Potato Famine of the late 1840s, the Irish flooded into southern Wales in Glamorgan and Monmouth counties. There they learned trades. At that point many stayed, while others immigrated with their new found skills. Destinations included the newly opened coal fields in northern England or to American cities such as Scranton and Pittsburgh in Pennsylvania. Another common migration was to eventually move on to New South Wales in Australia.
Cities with large Irish populations included Cardiff, Merthyr Tydfil, Swansea as well as the Rhondda Valley (between Cardiff and Merthyr Tydif). The heavy industry and mining jobs were not available in the southern part of Ireland so this was a new experience for these emigrants.
Typically, immigrants to these industrial areas came from counties Cork, Kerry, Kilkenny, Tipperary, Waterford and Wexford. The greatest numbers were from Cork and Tipperary. The Irish port of Rosslare, County Wexford provided a direct route to the Welsh port of Fishguard in Pembrokeshire.
Many Glamorgan records are available. The Glamorgan Family History Society www.rootsweb.ancestry.com/~wlsglfhs/ is a good place to start. Many of their indexes are available in major libraries. Never forget the collections of the Family History Library www.familysearch.org or the links provided on the UK & Ireland Genealogy (GENUKI) website: www.genuki.org.uk/big/wal/GLA/Pay special attention to their “Archives and Library” link for material not available outside of Glamorganshire.