Where's Bridget O'Toole?

I'm looking for Bridget O'Toole, born about 1827 in Clifden, Galway, Ireland.  She married Owen Lacey, also born in Clifden, Galway, Ireland.  I'm not sure if they immigrated to the US when their daughter, Winifred, immigrated about 1863.  Traditional thinking would say "Yes, because the daughter was only 10 years old."  The daughter settled in South Dakota, but I have yet to find the parents, Bridget and Owen.  I'd like to find Bridget, obviously because of the O'Toole name, but this is a name in a tree I'm working on for some San Diego O'Connors.  It would be fun to connect our trees!