Sources like the index and Ancestry.com do need to be taken with caution.
I've seen a mix of marriage records from the Iowa county court house.Some of that vintage list the parents names.I take it Francis & Elizabeth's did not.
What sources do you have for it being Eagan?Elizabeth death record?Children's death record?Just wondering since the four trees on Ancestry.com have Cagan.Ditto on the caution.
Using the 1860 census as a guideline, there were Eagans in Clyde and Highland.Mrs. Barney Eagan's obit said she "was born Co. Meath, Ireland in 1828, and in 1850 came to Pennsylvania, and in 1855, together with her husband, they located in Clyde."She died in Avoca.Many Eagans listed in Find A Grave in Avoca.
I had a Mrs. Eagan in elementary school many years ago.Still one Eagan in the Mineral Point phone book.