CPT Duncan was born in New York but spent the majority of his life in Estes Park, Colorado.  The Estes Park Trail issue of 2/7/1941, spoke of the death of his father Judge Duncan; the Judge was called an Estes Park pioneer who had lived there for 35 years, well beyond his son's lifetime.  On March 25, 1934 Joseph Duncan Jr. was an accomplished skier and won the United States downhill national championship by skiing down the "terrifying course" in Hidden Valley in 2 minutes, 58.2 seconds (Trail, 3/30/1934). By 1935 he was President of the Snow Club at Estes Park (Trail, 4/5/1935); on 9/10/1936 he was awarded a scholarship at Dartmouth College and departed for there, the newspaper noting "Young Duncan is the son of Judge J.J. Duncan and has lived here all his life." By that point he was a ski instructor for the Alberg Club, the most prominent skiing club in Colorado, and had also worked at the Estes Park post office the past 3 summers. In the 1940 census he was living at San Valley in Idaho; by the time of his father's death he was living in New York. CPT Duncan's entry into service is unknown to us, but he returned to Colorado as a member of the 87th Regiment, 10th Mountain Division, in 1942 after Camp Hale was instructed to very actively recruit skiers - he would've been among the first they contacted.

From the Estes Park Trail of 6/22/1945:

"Word has just been received in the Village of the death in Italy of Capt. Joseph Jonathan Duncan, son of the late Judge and Mrs. J.J. Duncan of Estes Park. He was killed April 17 in action while surveying artillery fire and directing his men. According to a letter from his sister, Mrs. James Johnson, "An enemy mortar shell exploding nearby killed him instantly." Survivors are his wife, Audrey, who has spent much of her life in Paris, who works for the French coordinating council in New York City where she makes her home, a small daughter; two sisters, Mrs. James Johnson of Wilmington, Calif., and Miss Alice Duncan, who is employed with the Palm Springs "Lime-Light-News." Capt. Duncan received his education in the schools of Estes Park and was graduated with the class of 1931 from the high school here. Captain Duncan was famous for his skiing and had appeared in many ski meets throughout the United States. He had been an instructor at Sun Valley, before he entered the armed forces. He underwent his training at Camp Hale, Colo., and was a member of the ski troops in Italy."