West Fargo is a city in Cass County, North Dakota, United States. It is, as of the 2020 census, the fifth most populous city in the state of North …West Fargo is a city in Cass County, North Dakota, United States. It is, as of the 2020 census, the fifth most populous city in the state of North Dakota with a population of 38,626, and it is one of the state's fastest growing cities. The city is part of the Fargo-Moorhead, ND-MN Metropolitan Statistical Area.