According to the Proclamation of 1763 at the end of the French and Indian War,

After Britain won the Seven Years' War and gained land in North America, it issued the Royal Proclamation of 1763, which prohibited American colonists from settling west of Appalachia. The Treaty of Paris, which marked the end of the French and Indian War, granted Britain a great deal of valuable North American land.

Explanation:

The Treaty of Paris, which marked the end of the French and Indian War, granted Britain a great deal of valuable North American land.