The Cimarron River, also known as the Buffalo Fork, is a river in the southwestern United States that runs through Colorado, Oklahoma, Kansas, and New Mexico. It is a tributary of the Arkansas River and is approximately 698 miles long. Synonyms for the Cimarron River include the following: the Cimarron, the North Canadian River, the Salt Fork Arkansas River, and the Beaver or Beaver River. This river played an important role in the history of the American West, as it was a popular route for settlers and traders to move westward. Today, it remains a popular destination for outdoor enthusiasts seeking to fish, canoe, or hike along its banks.