Raphael W. Pumpelly (born September 8, 1837, Owego, New York, U.S.—died August 10, 1923, Newport, Rhode Island) was an American geologist and scientific explorer known for his studies and explorations of the iron ore and copper deposits in the Lake Superior region in 1866–75.
Pumpelly graduated from the Royal School of Mines at Freiberg, Saxony, in 1859 and explored coal deposits and loess formations in China before becoming the first professor of mining at Harvard University (1866–75). He then worked as a geologist for various states and for the federal government, as well as for the Northern Pacific Railway. He served as head of the New England section of the U.S. Geological Survey from 1884 to 1889, during which time he published important studies of the geology of the Green Mountains. In 1903 he led an expedition to Central Asia that resulted in several more important monographs. His scientific works include Geological Researches in China, Mongolia, and Japan (1867) and Archeological and Physico-geographical Reconnaissance in Turkestan (1905). His autobiography, My Reminiscences, was published in 1918.