Insignia Description
A gold color metal and enamel device 1 1/8 inches (2.86cm) in height overall consisting of a shield blazoned: Per fess Or and Azure, issuant from partition line two piles reversed and concaved, in honor point a fleur-de-lis, all of the last, in base a sun in splendor of the first. Attached below the shield a gold scroll inscribed "BOUTEZ EN AVANT" in blue letters.

Symbolism
The shield is blue for Infantry with gold, the tincture of the shield of the arms of the ancient province of Lorraine, where the organization served during World War I. The fleur-de-lis denotes that the service was in France. The arrangement of the piles suggests the "Middlewest" Division, by which designation it was known during World War I. The sun is taken from the State flag of South Dakota and is symbolic of the "Sunshine State."

History
The distinctive unit insignia was originally approved for the 356th Regiment Infantry on 7 May 1928. It was redesignated for the 356th Regiment on 30 Jan 1962.

Source: The US Army Institute of Heraldry