The main reason great Britain established the proclamation line of 1763 was to

The main reason Great Britain established the Proclamation Line of 1763 was to ensure that British culture and laws remained and flourished in Upper Canada. They were hoping that this would attract more British settlers to the province. Upper Canada is representative of what is now the English-speaking parts of Canada, so the nine provinces, where Quebec is the only province that speaks French and was historically seen as Lower Canada and was not included in the Proclamation Line of 1763.