What stopped the 13 colonies from moving west in the 1700s?

The 13 colonies were largely prevented from moving west in the 1700s due to British colonial policies and treaties, particularly the Proclamation of 1763, which restricted settlement west of the Appalachian Mountains to avoid conflicts with Native American tribes. Additionally, the British government aimed to control westward expansion to manage trade and maintain peace with Indigenous peoples. Economic factors and the challenging terrain also played a role in limiting westward migration.