I read your posting at the KINGHORN Forum with great interest, as it seems your Andrew KINGHORN presents another branch of the family that has previously been unknown to me. However, it's only since I started digging into this family line that I've come to know what I know now, and it's all mostly new stuff.
I don't find Andrew in my family of Canadian KINGHORNs. My Robert KINGHORN was born in Scotland about 1846. He was married in 1871 in Cobourg, Ontario, lived awhile in Peterborough, and in 1881 homesteaded to northern Michigan (Stalwart).
I have met through his posting here at the KINGHORN Forum a Stan Johnson whose KINGHORN family resided in and around Lindsay, and I still believe that, because of it's proximity to Cobourg and Port Hope, where my grandmother Agnes KINGHORN returned to (she was born in Michigan), the families of the two otherwise separate KINGHORN lines MUST be linked somehow. I suppose I believe it to be too coincidental. But I have just gone through the names and dates that I have from Stan, and I don't find an "Andrew". (I would still suggest you contact him directly - he may be able to guide you somewhere I can't).
The 1871 Ontario Census lists 5 KINGHORNS, but none of them in the area of Barrie.
OCFA shows only 3 KINGHORNs in Ontario, all female (no dates researched).
Lynn, where do you live now, and can you provide any other names of siblings for Andrew? Do you have anything else you can share that may provide a clue. My resources are rather limited, but I do have a few notes on Ontario KINGHORNS that didn't work out to be my family.