Traill county is located in eastern North Dakota with Hillsboro acting as the county seat. The county population on July 1, 1999, was 8,555, a decrease of 197 over the 1990 census.

The Goose River flows from west to east through the midsection of the county while the Elm River courses through the southern portion. Both empty into the Red River of the North which forms the county's eastern border with Minnesota.

Educational assets include Mayville State University in Mayville.