In addition to his interest in the Red River Valley, Mr. Johnson had a consuming interest in the events surrounding the defeat of General Custer at the Battle of the Little Bighorn. He was a member of a number of historical societies in North Dakota, Minnesota, Montana, and Manitoba. In 1958 he was appointed to the advisory council of the Civil War Centennial Commission, and in 1960 he served as a historical adviser for the Dakota Territorial Centennial Commission, plus two committees for the Minnesota centennial observances. His papers are maintained at the North Dakota State University Institute for Regional Studies, in Fargo, North Dakota.