Ruso is an incorporated tiny city in McLean County, North Dakota, in the United States. The population was 1 at the 2020 census, making Rus…Ruso is an incorporated tiny city in McLean County, North Dakota, in the United States. The population was 1 at the 2020 census, making Ruso the least populous incorporated place in North Dakota. It is tied with Monowi, Nebraska, as the least populated community in the United States that is currently inhabited. There are no longer any businesses or services in Ruso; but said to be present is a FLDS compound that has been of concern to the Attorney General of the state.