The 66th Armor Regiment is the oldest armored unit in the United States Army, tracing its lineage to the 301st Tank Battalion which served with distinction soon after it was formed in the First World War; the 301st trained at Camp Meade, Maryland, where then-Cpt.

The 1st and 2nd Provisional Brigades of the United States Tank Corps would eventually go on to provide the original cadre for what would become the 66th Armored Regiment in World War II.

In September 1918 both brigades – which were attached to the 1st Infantry Division in France – participated in the battle of St. Mihiel and the Meuse-Argonne Offensive, operating French-built Renault FT tanks.

[5] When the regiment received its first two light tanks, unit members decided to name one for Magruder, and his wife took part in the christening ceremony.

In December 1942, the regiment was part of the amphibious invasion of Morocco in North Africa and led the division's entry into Casablanca.

In a difficult battle in the streets of the village of Percy and on surrounding high ground on 30 July, against some of the eight Panthers Generalleutnant Fritz Bayerlein had found and rallied from workshops at neighboring Villebaudon on 28 July, the 3/66th was to lose 13 tanks and was forced to pull out of the city losing another five tanks outside Centry to heavy Nebelwerfer and other mortar fire.

On 14 June 1944, just after arriving in France, the regiment was reorganized to align with newer armored division structure.

Captain James M. Burt, the commander of B Company, 66th Armored Regiment, was awarded the Medal of Honor for his heroism during the Battle of Aachen in October 1944.

In 1991, during Operation Desert Storm, the regiment assisted in the liberation of Kuwait and the defeat of the Iraqi army.

In the spring of 1995, the 1st Battalion of the 66th was assigned to assist over 5,000 Cuban and Haitian refugees interned at Guantanamo Bay, Cuba.

1-66 Armor subsequently deployed to Afghanistan in 2010-2011, as part of the Surge in the volatile Arghandab River Valley west of Kandahar City in RC-South.

For its conduct during its second deployment to Iraq, 3-66 Armor was awarded the Army Meritorious Unit Commendation in 10 March 2010.

This article incorporates public domain material from Lineage and Honors 66th Armor (Iron Knights).