Sanborn is a city in Barnes County, North Dakota, United States. The population was 161 at the 2020 census. Sanborn was founded in 187…Sanborn is a city in Barnes County, North Dakota, United States. The population was 161 at the 2020 census. Sanborn was founded in 1879. A post office has been in operation at Sanborn since 1879. The city was named in honor of J. N. Sanborn, an early settler. The town was an early contender for the county seat of Barnes County, but lost this role to Valley City in 1880. Its population declined after better roads allowed nearby farmers to trade in Valley City instead.