Milk River Natural Area is a provincially designated protected area in the southeastern corner of the province of Alberta, Canada, approximately 160 km south of the city of Medicine Hat. It lies primarily in the County of Forty Mile with a small portion in southwest Cypress County. On the Alberta Township System (ATS) grid it is located in portions of Township 1, Range 5 and 6, and Township 2, Range 6, west of the Fourth Meridian. At 5,344 ha (13,205 acres), Milk River was designated in June 1987 as an Order-in-Council Natural Area for conservation purposes under the Wilderness Areas, Ecological Reserves, Natural Areas and Heritage Rangelands Act and is Alberta's 100th Natural Area. It is owned by the provincial government as Public Land and administered by the Cypress District Office of Alberta Tourism, Parks and Recreation. Milk River Natural Area sits on the international border with the United States with Montana to the south, and is adjacent to the Kennedy Coulee Ecological Reserve to the west, with Pinhorn Provincial Grazing Reserve just beyond Kennedy Coulee. Other protected areas nearby include the Onefour Heritage Rangeland, Writing-on-Stone Provincial Park, and Cypress Hills Interprovincial Park. Access to Milk River Natural Area is challenging due to its remoteness and weather conditions: local roads and trails are impassable during or after wet weather, there is little to no cell phone coverage, and permission must be obtained when crossing grazing lease areas. However, this has helped maintain the area's relatively undisturbed condition and protected it from significant human impact. Canoes, kayaks, and inflatable rafts on float trips occasionally ply the waters of the Milk River through the Natural Area. While "no-trace" camping is permitted, it is not encouraged, and there are no visitor facilities provided. Natural and human history Geologically, the Milk River Natural Area is part of the Oldman and Foremost Formations, consisting of sandstone, siltstone, and carbonaceous shale, with isolated occurrences of igneous Sweetgrass Hills intrusives. The most prominent feature of the natural area is the Milk River Canyon. At up to 1,500 meters wide and 150 meters deep, it is the deepest in the Canadian plains. One of only five exposed igneous dikes in the Canadian plains, nicknamed the "Rooster Comb" for its distinctive size and shape, lies in the natural area. The Milk River itself is the only river in Alberta that flows to the Gulf of Mexico, joining the Missouri