The ranch was founded by John Devine in 1869 when he trailed his cattle herd from California to Fort C. F. Smith, a military outpost, on Whitehorse Creek. This was to become the headquarters of the Whitehorse Ranch. The Whitehorse Ranch was the first ranch established in Harney County. John Devine was a man that claimed and owned a number of large ranches in the area. He used the Whitehorse as his home and built the landmark barn for his race horses. The barn, with the life like miniature white horse gracing the top, is still in excellent condition and still in use.

Devine fell upon hard times and in 1889 the ranch was purchased by Miller and Lux perhaps the largest ranching concern ever in the West, with properties from the San Joaquin Valley in California to 150 miles north of the Whitehorse. At the company’s peak, they owned over a million acres upon which thousands of cattle wore the HH brand, ownership of which is included in the sale. In 1945 Paul Stewart purchased the property and during his tenure the irrigation and feed production of the ranch was greatly increased. The ranch drilled wells to supplement the creeks, put in alfalfa, produced corn for silage for winter feeding of the calf crop and increased the size of the wild hay meadows. Ted Naftzger purchased the ranch in 1961 and has continued to improve the ranch with the addition of deeded acreage, more water developments, land trades with the BLM to aggregate the deeded land and continued maintenance of the ranch infrastructure. The ranch, though a large agricultural enterprise, maintains much of the old west feel. The Whitehorse operates today much as it did one hundred years ago.