This is right beside Highway 40 west of Longview, Alberta.
From a sign on the post:
"John J. Sullivan, and Irish-born miner from Montana, turned to ranching and in 1884 ran his herd into the North-West Territories near the site of present day High River. In 1887, Sullivan was married to Barbara Harkley in Saint Mary's Church, Calgary, by Father Albert J. Lacombe, and the couple took up residence at this ranch site the following year. The first settlers to move into this valley, the Sullivans soon built their property into a first-class horse ranch.
Tragedy struck in 1894 when the Sullivan family fell victim to diphtheria. Despite the desperate efforts of Mrs. Walter Ings of the O H Ranch to nurse the children back the health, three of the four children died: Margaret, aged six; two year-old Patrick; and Peter, aged fourteen months. The Sullivans had four more children in the ensuing years, but in 1905 tragedy again befell the family when John was dragged to his death by a runaway horse. Brokenhearted, Mrs. Sullivan and the children moved to High River.
James Gordon Bews, who worked for Sullivan, purchased the property from the estate in 1910. The ranch has remained in the Bews family ever since and their operation is visible close to the river on the north side of the road."