Cogswell is a city in Sargent County, North Dakota, United States. The population was 73 at the 2020 census. Cogswell was founded in 189…Cogswell is a city in Sargent County, North Dakota, United States. The population was 73 at the 2020 census. Cogswell was founded in 1890. According to the United States Census Bureau, the city has a total area of 0.33 square miles, all land.