A 3-cent bright violet stamp was issued on July 15, 1938, to commemorate the 150th anniversary of the settlement of the Northwest Territory under the Ordinance of 1787. The first permanent settlement in the Territory was established in Marietta, Ohio. The Territory included Ohio, Indiana, Illinois, Michigan, Wisconsin, and part of Minnesota.
The stamp features sculptor Gutzon Borglum's statue "March Westward of the Nation', which stands in Marietta. Burglum also designed South Dakota's Mount Rushmore.