With Count Harald Moltke and Knud Rasmussen Mylius-Erichsen formed the Danish Literary Expedition (1902–04) to West Greenland, and, in the early stages (1902), discovered, near Evighedsfjord, two ice-free mountain ranges.
As commander of the Denmark Expedition (1906–08) Mylius-Erichsen undertook and carried out the task of exploring and charting the entire coastline of unknown northeast Greenland by three months' field work.
Their explorations showed that Robert Peary's chart of a coast trending southeast from Navy Cliff was radically incorrect.
[1]Mylius-Erichsen established the continuity of Greenland from Cape Farewell, 60° N, to the most northern land ever reached, 83° 39' N. He also discovered and explored the great fiords of Danmark, Hagen, and Brønlund.
Some cairn reports, left at Danmark Fjord by Mylius-Erichsen, were found and brought to Copenhagen by Ejnar Mikkelsen in 1912.