History: American Old West, United States

In 1910 the last conflict of the Old West began when Mexican Carrancistas rebelled against their government. Fighting spread all across Mexico and along the Mexican-American border, several battles were fought between American soldiers and citizens against Mexicans. On many different occasions Mexican bandits crossed the border and raided American settlements. Also, thousands of Americans joined the rebellion in Mexico and fought at all of the major engagements in the north including the Battle of Ciudad Juarez in 1911 and the Siege of Naco in 1914. In 1916 an army of American cavalry invaded Mexico as part of the Punitive Expedition, an attempt to capture the famous border bandit and rebel Pancho Villa. By the end of the revolution the Old West era was coming to an end with the rise of modern society in the region.
End of the Old West
After the eleventh U.S. Census was taken in 1890, the superintendent announced that there was no longer a clear line of advancing settlement, and hence no longer a frontier in the continental United States. However, according to author Samuel Eliot Morison, in 1890, when the frontier was declared "over", there was still thousands of square miles of unsettled land which took another few decades to populate or utilize. In his highly influential Frontier Thesis in 1893, Frederick Jackson Turner concluded that the frontier was all but gone. But with the discovery of gold in the Klondike in 1896, a new frontier was opened up in the vast northern territory. Alaska became known as "the last frontier".