Final answer:
The British government's Proclamation of 1763 prohibited western settlement to avoid conflicts with Native Americans, minimize frontier defense costs after the French and Indian War, and to maintain control over tax collection and imperial law enforcement.
Step-by-step explanation:
The British government issued the Proclamation of 1763 to prohibit settlement west of the Appalachian Mountains following the French and Indian War. The main reasons for this prohibition were to prevent further conflict with Native American tribes in the Ohio Valley, to avoid the costs of defending new frontiers, and to maintain control over the colonies for tax collection and enforcement of imperial laws.
Colonists, expecting to settle on these newly acquired western lands, were frustrated and saw the Proclamation as an act of tyranny. Furthermore, the British no longer required colonists to settle on the frontiers as a defense against the French and Native Americans, because the threat was eliminated with the British victory in the Seven Years' War.