The holdings of the Arapahoe Ranch have been in use for raising livestock since 1870. The ranch was started by Colonel George Sliney. Sliney’s lasting imprint on the Ranch is the irrigation ditch system, there is still a ditch just north of the Ranch Headquarters called the Sliney ditch. In the early days it was a sheep operation and was known as the Padlock Ranch. Sometime before 1918 the Padlock Ranch was purchased by a Midwest Industrialist by the name of Lee Simenson.