Barbed wire is a type of steel fencing wire constructed with sharp edges or points arranged at intervals along the strand(s). It is used to construct inexpensive fences and is used a top walls surrounding secured property. It is also a major feature of the fortifications in trench warfare (as a wire obstacle).
In April 1865 Louis François Janin proposed a double wire with diamond-shaped metal barbs; he was granted a patent. Michael Kelly from New York had a similar idea, and proposed that the fencing should be used specifically for deterring animals.
More patents followed, and in 1867 alone there were six patents issued for barbed wire. Only two of them addressed livestock deterrence, one of which was from American Lucien B. Smith of Ohio.Before 1870, westward movement in the USA was largely across the plains with little or no settlement occurring. After the American Civil War the plains were extensively settled, consolidating America's dominance over them.