In American speak...mrs bambu grew up on a ranch.
Cattle, sheep, crops, river thru the ranch. Not the 'Mississippi', just a nice little river.
Ranching...how do you keep the cattle and sheep from entering the paddocks of crops?
You build fences, strong fences, barbed wire!
How do your keep your neighbour's cattle and sheep from entering your ranch and eating the crops, grass etc, overrunning the land, drinking all the water in the dams set up for your herd/flock only?
You build fences, strong fences, and you patrol them often, fixing any 'holes'.
Countries are, in reality, just large ranches.