The Rocky Mountain Locust inhabited a large range., including Alberta, Manitoba, and Saskatchewan in Canada and Arizona, Colorado, Iowa, Kansas, Minnesota, Montana, Nebraska, North Dakota, Texas, and Wyoming in the USA.
The full-grown adults reached lengths of about 3 cm.
The species formerly formed seasonally swarms of giant sizes, which then devastated large areas of North America, destroying countless crops, and causing famines.
It is said that the locust plague did not spared cotton clothing or leather when found, and it is furthermore claimed, that they may have even eaten wooden fencing posts.
These last assertions, however, are probably pure fantasy.
The last large swarms were recorded in the years between 1873 and 1877, the last specimens were finally collected in Manitoba, Canada in 1902.
The reasons for the extinction of this once so common species are not well known, but it has been argued that plowing and irrigation by settlers in the Great Plains disrupted their natural life cycle in the areas they lived in, so it is reported that farmers destroyed over 150 egg cases per square inch while plowing, harrowing or flooding. 
 Jeffrey A. Lockwood: Locust: The Devastating Rise and Mysterious Disappearance of the Insect that Shaped the American Frontier. New York: Basic Books 2004