James Barney Marsh (1856–June 26, 1936) was an engineer and bridge designer born in North Lake, Wisconsin. He was a graduate of Iowa State College of Agriculture and Mechanical Arts in Ames.
He is known for reinforced concrete arch bridges, which he holds a 1911 patent for, throughout the United States. An example is the Cotter Bridge in Arkansas. The Big Creek Bridge in Oregon is similar in design. Several of these bridges remain and are listed in the National Register of Historic Places.
Hundreds of Marsh "Rainbow" bridges were constructed in the 1910s, 1920s and 1930s because of their popular design and appearance.
Marsh is buried in Glendale Cemetery, Des Moines, Polk County, Iowa with members of his family.[1]