I'm in the midst of perusing a book borrowed via inter-library loan from the Stormont, Dundas and Glengarry Library (in Cornwall??) entitled Bibliography of Glengarry County by Royce MacGillivray published in Alexandria, ON by the Glengarry Historical Society in 1996. I can only keep it till Apr. 24 so if you're close by you could put a reserve on it for when it arrives back "home." It's a reference book only and can't go out of the library. In the index on p220 look up "Cheddar Cheese Factories" - there are many references to cheese factories, cheese-making championships, a list of factories and creameries (p. 27) & reference to a map showing 61 cheese factories in Glengarry in 1931.