Hi Leah, I have only come across the name Leah Kernaghan once, that is in the 1881 British Census in Portsea, Hampshire, England. The entry shows Leah Kernaghan aged 20, her brother Thomas James, aged 27, and their mother Mary, a widow, aged 47. They are all shown as having been born in Ireland. Leah would have been born in 1861 which puts her in about the same era as your Matilda, as this is before the Civil Registration of Births in 1864 I cannot tell where she was born exactly. You might be able to get some assistance from the Ulster Historical Foundation on www.uhf.org.uk who may be able to locate the family pre civil list. When I get a chance I will check the Census for 1871 to see if they were in Portsea at that time, it may give an idea when they came to England from Ireland.