Originally founded as Denwood in 1905, the town of Wainwright was re-located three miles (5 kilometers) to the west-northwest where in 1908 the Grand Trunk Pacific Railway had surveyed a new site which was deemed more suitable to their needs. The town was given its new name for General William Wainwright, the second Vice-President of GTPR and it served as a western divisional point for the railroad. As a divisional point, it was intended that branch lines would extend from there to such places as North Battleford, Medicine Hat, Calgary, and the Peace River area. These intentions triggered a quick growth in Wainwright which became a village in 1908 (pop. 450) and was incorporated as a town on August 14, 1910 (pop. 1,000). Although the plans of the GTPR did not materialize, Wainwright maintained its position as a railroad center and became the major service center for the surrounding agriculture industry.
In 1908, to preserve the endangered bison, the Canadian Government created the original Buffalo National Park on 234 square miles of land immediately south of the town. The area was fenced and stocked with several hundred head of buffalo from Montana. The herd grew to such an extent that annual round-ups began in 1921, with some live animals shipped to various parts of the world others slaughtered. The round-ups continued until 1940 when all animals were removed and the park was turned over to the Department of National Defense (DND). By that time over 48,000 head of bison had been produced in the park.