On an olive drab disc 2 1/4 (5.72 cm) inches in diameter a green four leaf clover stem down displaying a red triangle point up.
The four leaf clover is for good luck and as displayed the four leaves make an "I". The three states in the Corps Area, Pennsylvania, Maryland and Virginia, are represented by the triangle and as the original white population of the three was English the triangle is made red. The three sides of the triangle together with the green "X" make up the number "13".
The shoulder sleeve insignia was approved for the 13th Corps on 7 Jun 1923. It was redesignated for the XIII U. S. Army Corps on 1 May 1958. A distinctive unit insignia for the XIII U.S. Army Corps was not approved. (TIOH Drawing Number A-1-69)