Insignia Description
A gold color metal and enamel device 1 1/8 inches (2.86cm) in height overall consisting of a shield blazoned: Azure, on a fess wavy Or between a fleur-de-lis and a patriarchal cross botonny Argent, four oak trees Vert (trees not to be connected at base). Attached below the shield a Blue scroll inscribed "QUI ME TANGIT PAENITEBIT" in Gold letters.

Symbolism
The shield is blue for Infantry. The wavy fess with its green oak trees signifies the Meuse River and the Argonne Forest; the fleur-de-lis represents service in France in World War I; the patriarchal cross botonny identifies the regiment with the 79th Division; the unit's former assignment.

History
The distinctive unit insignia was originally approved for the 315th Regiment Infantry, Organized Reserves on 2 Jul 1925. It was amended to add the motto for the 315th Infantry Regiment on 25 Oct 1956. On 20 May 1959 it was amended to withdraw "Organized Reserves" from the designation. The insignia was redesignated with description updated for the 315th Regiment on 1 Jul 1999.

Source: The US Army Institute of Heraldry