Wild West and the American Civil War

The American frontier, also known as the Old West or the Wild West, includes the geography, history, folklore, and culture in the forward wave of American expansion in mainland North America that began with European colonial settlements in the early 17th century and ended with the admission of the last few western territories as states in 1912. The archetypical Old West period is generally accepted by historians to have occurred between the end of the American Civil War in 1865 until the closing of the Frontier by the Census Bureau in 1890.
-Wikipedia