Hi
In the 1851 Wales census there is a family that matches the one you are looking for. The surname is transcribed as Rego but looking at the actual handwritten census return it can also be read as Keyo. The census was taken on 30th March 1851 and they are listed as living at 5 Crop St, Rhymney, Bedwelty, Monmouthshire. Those at the address are listed as Daniel Keyo, Head, 38, Labourer, (place of birth) Ireland; Bridget, Wife, 40, At home, Ireland; Margaret, Daughter, 13, At home, Ireland; Lawrance, Son, 10, At home, Glamorganshire; Jane, Daughter, 7, At home, Ireland; Michael, Son, 3, Monmouthshire; Mary Jacob, Visitor, 60, Widow, Ireland; Pathric Jacob, Nephew, 20, Railman, Ireland; John Limon, Lodger, 21, Labourer, Hereford; Daniel Hurn, Lodger, 21, Labourer, Ireland; John Lagrie, Lodger, 21, Labourer, Ireland; Thomas Ashurn, Lodger, 22, Labourer, Ireland; Peter Jacob, Visitor, 20, Labourer, Ireland (my ggg-grandfather).
It seems that they moved to Wales before emigrating. Hope this is useful to you.
Julie