Traill County, ND borders Grand Forks near Hillsboro metropolitan centre yielding a 2020 estimated census population standing at 8,235 making it the 12th most populous county situated in North Dakota overall. Its county seat is Hillsboro with other towns include Mayville & Portland-Hillsboro itself corresponds out to Traill’s biggesttown aside from recognized country seat. This area had been created out of Cass and Steele Counties back in 1875 when local residents petitioned for new administrative boundaries - posthumously named after Scotland barrister William Traill controlling region during period Ulysses Grant .