The American Old West comprises the history, myths, legends, stories, beliefs and cultural meanings that collected around the Western United States in the 1800s. Most often the term refers to the late 19th century, between the American Civil War and the 1890 closing of the frontier. Terms Old West and Wild West relate to life beyond the frontier. While this terminology could logically place the setting as far back as the American colonial period, the area from the "Frontier Strip" (i.e., the six U.S. states from North Dakota south to Texas) west to the Pacific Ocean is usually meant. Sometimes the tier of states just east of the Frontier strip (Minnesota to Louisiana) are also seen as the "Wild West" because of their stance as passing gates.

As the setting for numerous works of fiction, the period and region quickly became so popular that it now has its own genre, called "Western."

Historical revisionism has noted that certain interests (notably cowboys, Indians, businessmen, and the United States government) repeatedly clashed in these conflicts, and a few accounts refer to them as a "western civil war of incorporation" that established United States authority over the region. Violent small scale range wars between settlers, such as the Pleasant Valley War, Lincoln County War, and Johnson County Range War appear to have been common. Accounts of corrupt and criminalised justice systems are also common.