Two sons of Laurence Galvin of Westmeath, Ireland married two Duffy sisters, Rose and Susan. Lawrence Galvin married Rose Duffy in 1884 and Peter Galvin married Susan Galvin in 1892. All were from Ireland and moved to Chicago. The Galvins were from Castleton Geoghan, Westmeath, Ireland and the Duffys were from Dundalk, County Louth, Ireland.
The Galvin men's parents were Lawrence Galvin and ? and the Duffy girls' parents were Thomas Duffy and Bridget Shields. Thomas Duffy and a couple of his sons and Rose lived together after Lawrence died in Chicago and they are on the census.Rose was remarried to a man named Francis Brady and they moved to Omaha, NB.
I am distantly related to the Galvins and have been researching both families.I have done the one tree on the Galvins and another person did a wonderful job researching the Duffys and they have pictures of them on their tree.I am sure that if you bring up any of these names, the different trees will come up and you can view them.If not, I will try to help you as I can.