Young Blonde Girl Outside Near The Wooden Fence

In the United States, the earliest settlers claimed land by simply fencing it in. Later, as the American government formed, unsettled land became technically owned by the government and programs to register land ownership developed, usually making raw land available for low prices or for free, if the owner improved the property, including the construction of fences. However, the remaining vast tracts of unsettled land were often used as a commons, or, in the American west, "open range." As degradation of habitat developed due to overgrazing and a tragedy of the commons situation arose, common areas began to either be allocated to individual landowners via mechanisms such as the Homestead Act and Desert Land Act and fenced in, or, if kept in public hands, leased to individual users for limited purposes, with fences built to separate tracts of public and private land.
United Kingdom
Ownership of the fence varies. In some parts of the country all boundaries are shared; in other parts of the country you may own the boundary on the left-hand or right-hand side, however, only the title deeds can be depended on to tell you which side is yours. (A 'T' symbol indicates who is the owner). It used to be normal for the cladding to be on the non-owners side (enabling access to the posts for the owner when repairs need doing), but increasingly this cannot be depended on.