The area had been identified as a potential national park by virtue of a 1988 agreement between the governments of Canada and Saskatchewan. This agreement replaced a 1981 document when disagreements between the two levels of government arose concerning oil and gas exploration, and water management in the park area.

Grasslands National Park will eventually cover 900 square kilometres (350 square miles) in two blocks along the Canada - U.S. border in southwestern Saskatchewan. The federal government purchases the land on a willing-seller/willing buyer basis. There will be no expropriation.

As of 2005, the national park owns a total of 497.3 square kilometres (192 sq. mi.) in both the East and West Blocks. It may be several years before the park is completely established. However, there is a sufficient land base to pursue formalizing Grasslands National Park by including it in the Schedule of National Parks. This was achieved with the new Canada National Parks Act that received Royal Assent on October 20, 2000 and Proclamation on February 19, 2001. Also, a Draft Management Plan, developed by a Steering Committee comprised of parks personnel and various stakeholders, and supported by the public as witnessed during several open houses, has been submitted to the Minister.