The ML Ranch is significant in the area of agriculture for its association with the growth of the open range cattle ranching industry in Big Horn Basin during the last two decades of the nineteenth century. The ranch is also significant for its association with Henry Clay Lovell, important for his contributions to Wyoming's early cattle ranching industry in the Big Horn Basin. Lovell established the ML Ranch site as a line camp in 1883.

The following year it became headquarters for ranch operations. It became the largest cattle ranch in the eastern part of Big Horn Basin. During the heyday of open range, the ranch ran 25,000 head of cattle. The ranch typifies many similar profitable unions in which the ''know-how'' of a cattleman was combined with the assets of a financial investor from the east, in this case Anthony L. Mason.

The ML Ranch remained in the Lovell family until 1909. It changed hands a number of times before it was purchased by the Bureau of Reclamation in the early 1960s. In 1966 the ML Ranch buildings and the small parcel of land on which they are sited were acquired by the National Park Service.