 At one time, Wyoming was vast and open, suitable for growing large herds of livestock on the plains in the absence of fences. Much of Wyoming is still wide and open. However, the plains are criss-crossed with fences used to keep livestock in or out of certain areas. Wyoming is a fence-out state with regards to cattle. This means that landowners who prefer not to have cattle on their property are responsible for fencing them out. Interestingly enough, Wyoming is a fence-in state with regards to sheep. This is because sheep historically were under the guide of a herder. Wyoming law indicates that a lawful fence must be constructed to keep livestock in or out. Lawful fences are typically three or four lined barbed wire, like the ones we see here. Fences like these can be seen all across Wyoming, especially along highways. Each year, farmers and ranchers, highway department employees, and even people like yourself, spend countless hours fixing and building fence. From the University of Wyoming Extension, I'm Rachel Miller, Exploring the Nature of Wyoming.