Oscar A. Baarson was born in Madison, South Dakota, on November 16, 1889, the son of Bars Christian Baarson. He served for a time as assistant to the North Dakota State Geologist doing field surveys, and worked for the Homestake Gold Mining Company in Lead, South Dakota. In 1917 he graduated from the University of North Dakota School of Mines, and then went to work for the Cerro de Pasco Mining Company in Peru, and the following year for the Anaconda Copper Mining Company's Chuquicamata Mine in Chile. In 1922 Baarson began teaching high school science in Idaho. He then took graduate work at the University of Washington. After completing his graduate work he returned to Idaho as a teacher at Burley and then as superintendent of schools in Roberts. In 1928 Baarson moved to Great Falls, Montana, to work for the Anaconda Copper Mining Company, first at their Great Falls Refinery and then as assistant superintendent of the East Helena Slag Treatment Plant. From 1931 to 1933 he worked as a private mining engineer, and then in 1933 as a bridge inspector for the State Highway Commission. In 1935 he was hired as Helena City Engineer. One of his first tasks as city engineer was surveying earthquake damage from the 1935 Helena earthquakes. He worked for the city until the start of World War II, when he was hired as district manager for the U.S. War Production Board. After the war he resumed his private mine engineering business, until 1953 when he became Assistant State Engineer for the State Board of Examiners. In this position he evaluated the engineering plans for state buildings. During the 1960s Baarson served as deputy appraiser in the Lewis and Clark County Assessor's Office, and then as County Surveyor. Oscar Baarson was married to Camilla Walton and had five children: Robert, William, Barbara, Mary, and Beverly. He was active in the Episcopal Church, the Eagles Lodge, and the Morning Star Lodge of the Masons. Oscar Baarson died November 29, 1971 in Helena.