Denis A. St-Onge was born in 1929 in Ste-Agathe, MB. He earned a B.Sc in Geology from the University of Manitoba (Collège de St-Boniface) in 1951 and a L.Sc. from l'université de Louvain, Belgium in 1957. He then joined the Geographical Branch of the Department of Mines and Technical Surveys as chair of the Committee responsible for the translation of the Atlas of Canada. A year later, he became a member of the original group of the Polar Continental Shelf Project which took him to Ellef Ringnes Island, carrying out geomorphological surveys during the summers of 1959 to 1961. This work would form the basis of his doctoral dissertation for the D.Sc. granted by l'université de Louvain in 1962. Dr. St-Onge worked as a research scientist with the Geological Survey of Canada from 1965 until 1973 with a two-year hiatus (1968-1970) as a professor at the University of Ottawa. He rejoined the faculty at the University of Ottawa in 1973, where he held a series of positions including Chair of the Department of Geography, Secretary of the Faculty of Arts and the Vice-dean of the School of Graduate Studies and Research. He returned to the Geological Survey in 1982 as chief of the Quaternary Geology Subdivision and later Director of the Terrain Sciences Division. As an Emeritus Scientist, he served as Scientific Advisor to Polar Shelf and as research scientist with Terrain Sciences Division. St-Onge was also been active in many national and international bodies. He was the first chair of the Canadian National Committee for the International Union for Quaternary Research (INQUA) and was Vice-President of the organizing committee for the 1987 congress. He also served as President of the Canadian Association of Geographers, President of the Geological Association of Canada, Vice-President for External Relations of the Canadian Social Sciences Federation and President of the Royal Canadian Geographical Society. In May 1996, he was elected President of the Canadian Geoscience Council. Among his many honours are Honorary Membership in the Société géographique de Belgique, a commemorative medal of the reign of Queen Elizabeth II in 1979, the medal of the université de Liège in 1980, Honorary Doctorate in Science from the University of Manitoba in 1990, membre honoraire (médaille André Cailleux) from the Association québécoise pour l'étude du Quaternaire in 1991, and election as Honorary Life Member by the General Assembly of INQUA also in 1991. The Arctic Institute of North America made him a Fellow in 1994. In September 1994, he was awarded the Scottish Geographical Medal by the Royal Scottish Geographical Society and in 2002 he was appointed chair of the FLUXNET, a national research network studying carbon cycling. He was named an Officer of the Order of Canada in May 1996. As of 2020, St-Onge was Emeritus Professor in the Department of Geography, Environment and Geomatics, at the University of Ottawa.