This one, I'm pretty sure, was in Canada, and was held annually for several years in the 60's & 70's.
Probably stopped after the 70's.
I remember it because it was an odd distance (like Bloomsday/Falmouth/Bay to Breakers)....maybe 7.6 miles (or 12K).
T&FN covered it in their Road Report they had for many years back then.
Big name runners ran it.....before the African explosion.
If you have access to T&FN's of that period (I used to!!!), you'd find references to it.....with results, etc.
Maybe GH would remember.....or a runner who ran the race!!