The American explorer and scientist Donald Baxter MacMillan (1874-1970) surveyed and mapped unknown land and water in the Arctic.

Donald MacMillan was born in Provincetown, Mass., on Nov. 10, 1874, the son of a ship captain. He was orphaned at an early age. He attended Bowdoin College in Maine, graduating in 1898. For the next few years he taught school and conducted a summer camp at Casco Bay, Maine, where he met explorer Robert Peary. MacMillan signed on for the expedition that became Peary's first, after two decades of effort, to reach the North Pole (April 6, 1909). The intrepid explorer's eventual success was dependent upon capable support parties, one of which MacMillan led.

MacMillan's initial Arctic experience inspired him to make northern exploration his life's work. After exploring the interior of Labrador in 1910, he began postgraduate work in anthropology at Harvard University. In 1911 and again in 1912 MacMillan returned to northern Labrador to...