Солтүстік Дакота штатының Трейл округі

County in North Dakota, United States

Traill County is a county in the U. S. state of North Dakota. As of the 2020 census listed the population at 7,997. Its county seat is Hillsboro, and its largest city is Mayville.

The Dakota Territory legislature created the county on January 12, 1875, with areas partitioned from Burbank (now Barnes), Cass, and Grand Forks counties. It was named for Walter John Strickland Traill, an employee of the Hudson's Bay Company and son of Canadian pioneer Catharine Parr Traill. Construction of the current county building began in 1905; it is now listed on the National Register of Historic Places. The county boundaries were altered in 1881 and in 1883. It has maintained its current configuration since 1883.

Traill County lies on the east side of North Dakota. Its east boundary line abuts the west boundary line of the state of Minnesota (across the Red River). The Goose River flows eastward through the center of the county to discharge into the Red. The northward flowing Red River forms the eastern boundary line of the county on its way to the Hudson Bay, and the Elk River flows south southeastward through the southwestern part of the county. The county terrain consists of rolling hills, devoted to agriculture. The terrain slopes to the east and north, with its highest point on the lower western boundary line, at 1,201 feet (366 m) ASL. The county has a total area of 863 square miles (2,235 km2), of which 862 square miles (2,233 km2) is land and 0.6 square miles (2 km2) (0.07%) is water.