What route did your Phelan ancestors take in North America?

I have still not been able to find a starting point for my Phelans in Ireland. 

What I do know is that they were in Ontario, Canada mid-late 1850s and then left there for the U.S.  I have decades of records placing them in St. Louis, MO, Murphysboro, IL and Memphis, TN.

I don't know if they left Ireland for Canada first or the U.S. and then relocated (temporarily) to Canada before settling in the U.S.  No record of immigration has been found.

Names that I have include:  John Phelan (c. 1830), his wife Bridget Buckley both born in Ireland.  Their son, Jeremiah Joseph Phelan (b. 1856, Canada) and his children all born in the U.S.