From the April 11, 2011, Northwest Indiana Portage News "U.S. 6, U.S. 12 memorials to Civil War soldiers" by Joyce Russell.
US-6 is the Grand Army of the Republic Highway. It was the idea of Major William A. Anderson of the U.S. Army in 1934. This idea was strongly promoted by the Sons of Union veterans of the Civil War( SUVCW) The Grand Army of the Republic (GAR) was a group made up of veterans from the Union side during the war.
US-6 starts in Massachusetts and is a transcontinental highway, ending in California. The idea had to be approved by each state for the GAR Highway to come into existence. Massachusetts was the first to approve it in 1937. Indiana was the last in 1946.
The formal dedication took place May 2, 1953, in Long Beach, California
The highway runs through 14 states and covers 3,652 miles. That is more than the more famous Route 66.