[Docere]

- Eastern Ontario is more French Canadian and Irish, SW Ontario is more German and Dutch

- SW Ontario has more evangelicals (Baptists, Mennonites, Dutch Calvinist etc.) - largely though not entirely related to the German/Dutch presence.

- Eastern Ontario has a more visible UEL presence even today. SW Ontario had more settlers (from both Britain and the US) with more democratic and populist tendencies, making it a stronghold for the Liberals (Clear Grits) in the 19th century and the United Farmers of Ontario after WWI. It was also the main bastion of the Ontario Liberals up until the 1970s.

- SW Ontario is probably more "socially conservative" on issues like abortion because of the larger evangelical presence. Eastern Ontario takes the more traditional or conservative position on issues like support for the military and monarchy (in addition to the Loyalist culture of Eastern Ontario, SW Ontario has pockets, particularly German-settled areas, with a more complicated relationship to the military and monarchy).

- In terms of economy, SW Ontario has more prosperous agricultural areas and is also part of the industrial heartland. Eastern Ontario would have more public employment (simply because Ottawa makes about half the population!)

- SW Ontario cities have a more "Midwestern" urban form than Eastern Ontario cities do.

I haven't defined it exactly - but I'm thinking that SW Ontario is more or less synonymous with the 519 area code or "N" postal codes, while Eastern Ontario = 613 or "K" postal codes.