Cass County, North Dakota

Cass County is a county located in the U.S. state of North Dakota. As of the 2010 census, the population was 149,778, and was estimated to be 175,249 in 2016. Cass County is the most populous county in North Dakota, accounting for nearly 23% of the state's population in 2016.

Its county seat is Fargo. It is the most populous city in the state. The county was organized on October 27, 1873.