Cass County is in the state of North Dakota encompassing a total area of 1,768 square miles. Cass County is the most populous county in North Dakota with around 195,000, accounting for nearly 25 percent of the state’s population. Its county seat is Fargo, the most populous city in the state.

Cass County lies on the east side of North Dakota. Its east boundary line abuts the west boundary line of the state of Minnesota across the river. The Red River flows northward along the county’s east boundary, on its way to Lake Winnipeg and Hudson Bay. The county’s terrain consists of low rolling hills and flat plains, devoted to agriculture except around developed areas.

Cass County is governed by a board of commissioners elected to four-year terms. Other elected officials include the Sheriff and State's Attorney.