The crest was approved by the Department of the Army and the 9th Engineer Battalion on 27 July 1967. All the symbols reflect the battalion's initial service in the southwest United States. The wreath under the Gila monster is the Corps of Engineer wreath. The Gila monster represents service along the Gila River and the southwest desert from 1917-1920 (added to the insignia in 1925). The ship anchor and oars are the Coat of Arms from 9E's original parent unit, the 2nd Battalion Mounted Engineers. The horse head represents service as Mounted Engineers (1917-1941) and Armored Engineers (1941-1945). The wavy chevron running across the shield represents service along the Rio Grande from 1917-1920. The lone star on the bottom represents service in Texas from 1917-1921. The motto Asistiremos was added in 1925, meaning We Will Assist in Spanish.