Over the past 110 years, 14 220 boys have been named Duncan. The name Duncan ranks 815th in the United States among the most common names for boys. For the first time more than ten times newborns were named Duncan in 1914. The peak of popularity of the name Duncan came in the 1990s and 2000s. You can see absolute numbers and relative numbers on the chart. Indicators per 100K more accurately assess the popularity of the name.