The median income of Billings County residents was an inflation-adjusted $41,027 per year. Billings County had 401 households in 2017, with a population of 983.
The county with the highest median resident income in the state was Williams County. Williams County's median income was $42,466 per year after adjusting for inflation – $1,439 more than Billings County. It had 12,895 households in 2017 and a population of 32,916.
Sioux County had the lowest annual resident income among counties in North Dakota, with a median income of only $22,396 per year. That was $18,631 less than the median income in Billings County at the time. Sioux County had 1,114 households in 2017 and a population of 4,420.
The table below shows the state's counties ranked by median annual resident earnings in 2017.