Billings County is a county in the U.S. state of North Dakota. As of the 2020 census, the population was 945, making it the second-least populous county in North Dakota. Its county seat and only incorporated place is Medora. The Territorial legislature authorized Billings County on February 10, 1879, naming it for Northern Pacific Railway president Frederick H. Billings. It was organized on May 4, 1886.