- Tioga City is a city located in North Dakota, United States. It is the county seat of Williams County and is situated in the western part of the state. The city has a population of approximately 1,600 residents as of 2020. Tioga City is known for its proximity to the Bakken Formation, an oil-rich region that has experienced significant growth in recent years. The city provides various amenities and services to its residents, including schools, healthcare facilities, parks, and recreational opportunities.