I have been doing a lot of research on the Dack family which came from Ireland to Ontario Canada, and then spread all over North America.
John Edward Dack, m. Jane Wiley Dec 24, 1862 in Illinois and moved to Nebraska between 1867 and 1877.
His brother Frederick Edwin Dack, m. Emma Godfrey April 20, 1879 in Illinois and was in Nebraska in 1904.
A cousin Charles David Dack m. 1. Margaret Osburn December 23, 1866 in Illinois, and 2. Catherine xx, ca 1874. Charles lived in Nebraska for a few years before moving to Kansas (ca 1875).
Another Cousin, Julia Ann Grant m. Theodore Kay, March 24, 1865 in Illinois. She died in Nebraska, but I have no information when she moved there.
I have all kinds of details linking these families back to Ireland, but nothing after them. Feel free to ask for more if any of this is of interest to you (and if you are still digging into this area).