The 640th Regiment Distinctive Unit Insignia, commonly referred to as a unit crest or a DUI, was first approved for the 640th Tank Destroyer Battalion on 27 February 1943. It was subsequently redesignated several times before being given its current designation, first in May 1951 for the 653rd Field Artillery Observation Battalion and again in April 1961 for the 140th Artillery Regiment. That insignia was amended to correct the translation of the motto on 22 April 1968 before it was redesignated for the 140th Field Artillery Regiment in July 1972. Nearly twenty years later, the insignia was redesignated for the 140th Utah Regiment on 10 December 1997, a little under three years before it was finally designated for the 640th Regiment.
The first role taken on by the Regiment is reflected in its DUI. Gold and black are used predominantly to reflect its service as a member of the Tank Destroyer Forces during World War II, with the Tank Destroyer “function of destruction” symbolized by the disjointed panther head, the flames emitting from its maw denoting the zeal with which Regimental personnel perform their duties. IGNE ET FERRIS VICIMUS, the unit motto, translates into English as “We Conquered By Fire And Swords.”
Since 1999, the 640th Regiment has been responsible for running and maintaining the Utah National Guard’s Regional Training Institute. The Institute provides training in certain Career Management Fields and Noncommissioned Officer Education System missions; these can vary over time based on the requirements identified by the Army Reserve, Individual Training Branch of the National Guard Bureau, the Army Program for Individual Training for the Army National Guard, and the Subject Matter Expert Regiment in support of the Army's Modular Force.
In the Summer of 2023, the Regiment’s four Battalions were responsible for the NCO Academy (1st Battalion), Modular/Signal Corps MOS training (2nd Battalion), Field Artillery training (3rd Battalion), and Military Intelligence MOS classes (4th Battalion).