Most of the literature attributes the walls to early settlers and colonists. The vast amount of walls especially in places that were never settled makes this hypothesis wrong and outright misleading. Some walls were created by colonists but you would need millions and millions to make all the walls in this region.

The early colonists were substitance farmers and there are no journals or diaries or documents which talk about building walls.

They do have diaries of farming and painting and all other topics but not building walls up mountains and sprawling over legde and landscapes.