European settlement brought about the decline of Aboriginal occupation of the desert. White settlers introduced influenza to the Aboriginal groups, decimating the population. Groups were displaced as pastoral properties took over their land, while other Aboriginal people were attracted to work on properties and to towns and communities.
The first European to see the grandeur of the Simpson Desert was the explorer Charles Sturt in 1845, but the desert was not fully recognised and named until the 1930s when another explorer and geologist, Cecil Thomas Madigan, named it after Allen Simpson, the sponsor of his subsequent expedition and then president of the Royal Geographical Society of Australasia (South Australian Branch). The explorers who came after Sturt, mainly government surveyors, named a number of the familiar landmarks in the area.
Notable among the early surveyors was Augustus Poeppel who surveyed the junction of the borders of Northern Territory, Queensland and South Australia in 1880. The original peg marking Poeppel Corner was removed to Adelaide for preservation in 1962 by Dr Reg Sprigg and now forms part of the History Trust of South Australia's Historic Relics Collection. On 25 August 1968, Bill Haylock of the SA Geodetic Survey placed the current steel and concrete post to mark Poeppel Corner. In 1989, the Friends of the Simpson Desert Parks erected a red gum replica of the original peg near the corner post.
The first successful European crossing of the desert was in 1936 and is credited to E. A. Colson, who, with Peter Ains (an Aboriginal companion) and five camels, travelled from Mount Etingambra eastwards via Poeppel Corner to Birdsville. Geologist Reg Sprigg and his family completed the first motorised crossing in 1962, with Dr Sprigg’s Geosurveys of Australia company.
In 1936, the French Petroleum Company was contracted to conduct seismic surveys and explore for oil and gas deposits. These workers spent months at a time in the desert, building what are now known as the French and QAA lines, Rig Road and other tracks, thus opening up the desert for other explorers, pastoralists and tourists to follow.
The Munga-Thirri–Simpson Desert Conservation Park was originally proclaimed as a national park in 1967, but changed to conservation park classification in 1972. The regional reserve was established in 1988, linking the conservation park with Witjira National Park. The enormous size of the parks (the regional reserve covers 29 191 sq km, the conservation park, 6 881 sq km) allows a wide cross-section of diverse flora, fauna and sand ridge formations to be protected.