Hello Greg,
I have just been into the website of the Pioneers of Henry County, Illinois, having a look at the information on Robert Corkill and Jane Kennish,
and I noted the Date of Death for Robert Corkill 18th January 1909
so decided to see if I could find a Gravestone Inscription or a Will for him, in America, that would help you with your family history,
I tried a search for 1909 Deaths, and there is no death in 1909 for a Robert Corkill in Kewanee, Henry County, Illinois

so I searched for a death after 1909 and have found,

Illinois Statewide Death Index, 1916–1950

CORKILL JANE KENNISH 1921-10-28 HENRY KEWANEE
CORKILL ROBERT 1937-01-23 HENRY KEWANEE

YOU NEED the Death Certificate of Robert Corkill
To see who his Parents are, before you can search back any further,
You need this death certificate TO PROVE you are on the RIGHT FAMILY

I have seen so many Family Trees that have been disproved, and years of work destroyed because they haven’t had the proof that is needed “on Paper”
If you don’t have the proof needed, then it just becomes “guess work”

I will look forward to reading your next posting, with all the information from the Death Certificate,

Averil