Underwood is a city in McLean County, North Dakota, United States. The population was 784 at the 2020 census. Underwood was founded alo…Underwood is a city in McLean County, North Dakota, United States. The population was 784 at the 2020 census. Underwood was founded along a Soo Line Railroad line between Bismarck and Max in 1903 and named after Fred D. Underwood, vice president of the railroad at the time. Alon Wieland, businessman and politician, was born in Underwood.