The 35th Infantry Regiment ("Cacti") was created on 1 July 1916 at Douglas, Arizona from elements of the 11th, 18th and 22nd Infantry Regiments. The 35th served on the Mexico–US border during the First World War and was stationed at Nogales, Arizona in 1918. It fought a border skirmish on 27 August 1918 during the Battle of Ambos Nogales.

In World War II, Korea, and Vietnam it served as part of the 25th Infantry (Tropic Lightning) Division.

As of 2012, the only active element of the regiment is the 2nd Battalion, which is assigned to the 3rd Brigade Combat Team (Infantry), 25th Infantry Division.

In October 2025, the 1st Battalion was activated and assigned to the 2nd Mobile Brigade Combat Team, 25th Infantry Division.

Heraldry The regiment's coat of arms and its distinctive unit insignia reflect its history. The regiment was originally formed in Arizona from elements of the 11th, 18th, and 22nd Infantry Regiments. These organizations are represented on the canton of the crest, in the upper left-hand corner. The white Maltese cross represents the 11th Regiment, the red acorn represents the 18th Regiment, and the embattled partition line of the canton represents the 22nd Regiment. The cactus represents the original service along the Mexico–US border against the revolutionaries of General Francisco Villa.

Distinctive unit insignia The following is a direct quote from the US Army The Institute of Heraldry regarding the 35th Regiment.

Description/blazon A gold color metal and enamel device in height overall consisting of a shield blazoned: Argent, a giant cactus Vert. On a canton embattled (for the 22nd Infantry) Azure, a cross patée of the field (for the 11th Infantry) charged with an acorn Gules (for the 18th Infantry).

Symbolism This regiment was originally organized in Arizona with personnel from the 11th, 18th and 22nd Infantry. These organizations are shown on the canton. During the Civil War the predecessor of the 11th Infantry was in the 2nd Division, V Corps, the badge of which was a white Maltese cross; the 18th Infantry was in the 1st Division, XIV Corps, with a red acorn as the badge. The 22nd Infantry is represented by the embattled partition line of the canton. The cactus represents the original service of the 35th Infantry on the Mexico–US border.

Background The distinctive unit insignia was originally approved on 28 Jun 1923. It was amended to change the method of wear on 30 Apr 1926.

Coat of arms The following is a direct quote from the US Army The Institute of Heraldry regarding the 35th Regiment.

Description/Blazon Shield Argent, a giant cactus Vert. On a canton embattled (for the 22nd Infantry) Azure, a cross patée of the field (for the 11th Infantry) charged with an acorn Gules (for the 18th Infantry). Crest On a wreath of the colors (Argent and Vert) a walnut tree Proper. Motto TAKE ARMS.

Symbolism Shield This regiment was organized at Douglas, Arizona, in July 1916 from the 11th, 18th and 22nd regiments of Infantry. These organizations are shown on a canton. In the Civil War the predecessor of the 11th Infantry was in the 2nd Division, V Corps, the badge of which was a white Maltese cross; the 18th Infantry was in the 1st Division, 14th Army Corps, with a red acorn as the badge. The 22nd Infantry was originally the 2nd Battalion, 13th Infantry and as such distinguished itself at the Siege of Vicksburg, receiving the name "First at Vicksburg." This is shown by the embattled partition line of the canton. The cactus represents the original border service of the 35th Infantry.

Crest The crest commemorates the baptism of fire of the regiment at Nogales, the Spanish for walnut trees.

Background The coat of arms was approved on 9 Apr 1920.

Motto The regimental motto is "Take Arms!" During the Battle of Ambos Nogales in 1918 when the alarm went out, officers, non-commissioned officers and soldiers shouted out, "Take Arms! Take Arms!"

World War I and Mexican Border War

In March 1917, the 35th Infantry moved to Camp Stephen D. Little, near Nogales, Arizona. It was assigned on 7 August 1918 to the 18th Division. The regiment was in the midst of relocating to Camp Travis, near San Antonio, Texas, to join the rest of the 18th Division when, on 27 August, at about 4:10 pm, a gun battle erupted unintentionally when a Mexican civilian attempted to pass through the border back to Mexico without being interrogated at the U.S. Customs house. After the initial shooting, reinforcements from both sides rushed to the border line. Hostilities quickly escalated and several soldiers were killed, and others wounded. Note: Library of Congress Number: 93-206790

The 35th Infantry border post had about 15–18 men, and requested reinforcements from their garrison. When they arrived, they requested the Buffalo Soldiers of the 10th Cavalry. The 10th, commanded by Lieutenant Colonel Frederick Herman, came to their aid from their camp outside of town. After observing the situation for a few moments, Herman ordered an attack on the Mexican and German held hilltops overlooking the border town. Defensive trenches and machine gun placements had been seen being dug there in the previous weeks. Herman wanted Americans there before Mexican reinforcements got there.

Under heavy fire, the 35th Infantry soldiers and dismounted 10th Cavalry troopers advanced across the Mexico–US border through the buildings and streets of Nogales, Sonora and up onto the nearby hilltops. This was done while other units of the 35th Infantry held the main line near the border post. About 7:45 pm, the Mexicans waved a large white flag of surrender over their customs building. Lt. Colonel Herman observed, and then ordered an immediate ceasefire. Snipers on both sides continued shooting for a little while after the ceasefire but were eventually silenced upon orders from their superiors.

Interwar period

The 35th Infantry Regiment was relieved from the 18th Division on 14 February 1919, and was transferred on 16 November 1919 to Camp Lewis, Washington. It sailed for the Territory of Hawaii on 20 September 1920 on the troopship USAT Great Northern. It arrived at Schofield Barracks on 25 September 1920, and was assigned to the Provisional Infantry Brigade; it was assigned to the 21st Infantry Brigade on 4 February 1921, and further assigned to the Hawaiian Division on 1 March 1921. It was relieved from the 21st Infantry Brigade on 14 October 1922 and assigned to the 22nd Infantry Brigade. The regiment's primary wartime mission was to conduct a mobile defense of the beaches and inland sectors of the southern half of the island of Oahu. It was assigned on paper to the 25th Infantry Division on 26 August 1941, with the headquarters of that unit activated on 1 October 1941.

World War II

The regiment was sent to Guadalcanal, 25 November 1942, to relieve Marines near Henderson Field. First elements landed near the Tenaru River, 17 December 1942, and entered combat, 10 January 1943, participating in the seizure of Kokumbona and the reduction of the Mount Austen Pocket alongside the 27th Infantry Regiment, in some of the bitterest fighting of the Pacific campaign. With other units on 5 February 1943, it helped end organized enemy resistance.

A period of garrison duty followed, ending 21 July: On that date, advance elements debarked on Munda, New Georgia. The 35th Infantry, under the Northern Landing Force, took part in the capture of Vella Lavella, 15 August to 15 September 1943. Organized resistance on New Georgia ended, 25 August, and the division moved to New Zealand for rest and training, last elements arriving on 5 December. The 25th was transferred to New Caledonia, 3 February – 14 March 1944, for continued training.

The division landed in the San Fabian area of Luzon, 11 January 1945, to enter the struggle for the liberation of the Philippines. It drove across the Luzon Central Plain, meeting the enemy at Binalonan, 17 January. Moving through the rice paddies, the 25th occupied Umingan, Lupao, and San Jose and destroyed a great part of the Japanese armor on Luzon. On 21 February, the division began operations in the Caraballo Mountains. It fought its way along Highway No. 5, taking Digdig, Putlan, and Kapintalan against fierce enemy counterattacks and took Balete Pass, 13 May, and opened the gateway to the Cagayan Valley, 27 May, with the capture of Santa Fe. Until 30 June, when the division was relieved, it carried out mopping-up activities. On 1 July, the division moved to Tarlac for training, leaving for Japan, 20 September. At the end of the war the 35th was involved with occupation duty in Japan.

The regiment had three Medal of Honor recipients during World War II, William G. Fournier, Lewis R. Hall and Charles L. McGaha.

Korean War

Open warfare once again flared in Asia, now the 25th division's primary area of concern, on 25 June 1950. The North Korean People's Army crossed the 38th Parallel on that day in an attack on the Republic of Korea (South Korea). Acting under United Nations orders, the Tropic Lightning Division moved from its base in Japan to Korea between 5–18 July 1950. The 35th fought out of the Pusan perimeter and was part of the successful drive into North Korea in October 1950. In a sudden and unexpected reversal, however, an overwhelming number of Chinese Communist troops crossed the Yalu and pushed back United Nations forces all along the front. The 35th Regiment was forced to carry out a systematic withdrawal and ordered to take up defensive positions on the south bank of the Chongchon River 30 November 1950. Eventually, these lines failed. However, after a series of short withdrawals a permanent battle line was established south of Osan. Then followed the see-saw battles that finally evolved into static warfare along the Iron Triangle into 1952.

The 35th Regiment with the rest of the 25th Infantry Division assumed the responsibility of guarding the approaches of Seoul 5 May 1953. 23 days later, when ceasefire negotiations at Panmunjom stalled, a heavy PVA assault hit the Nevada Complex, the Division held its ground; the brunt of the attack was absorbed by the attached Turkish Brigade and the 14th Infantry Regiment. By successfully defending Seoul from continued attack from May to July 1953, the division earned its second Republic of Korea Presidential Unit Citation. Again, negotiators moved toward peace. In July, the division again moved to reserve status at Camp Casey where it remained through the signing of the armistice 27 July 1953. Fourteen division soldiers were awarded Medals of Honor during the Korean War, making the division one of the most decorated US Army divisions of that war.

The regiment remained in Korea until 1954 and returned to Hawaii from September through October of that year. After a 12-year absence, the 25th Infantry Division had finally returned home.

The 35th Infantry Regiment had three Medal of Honor recipients in Korea, William R. Jecelin, Billie G. Kanell and Donald R. Moyer.

Vietnam

In August 1965, elements of the 35th Infantry started their rotation into the Vietnam War, arriving in South Vietnam. The 1st and 2nd battalions, along with the 1st Battalion, 14th Infantry, and the 2nd Battalion, 9th Artillery provided the core combat units of the 3rd Brigade, 25th Infantry Division and were deployed to the Central Highlands at Pleiku. Final units arrived by Christmas 1965. The battalions of the 35th Infantry were heavily engaged from January 1966 until 1972 throughout the I Corps and II Corps areas of operations (the Central Highlands and central coastal areas of Vietnam). In August 1967, operational control of the two battalions of the 35th Infantry and all of the other parts of the 3rd Brigade were transferred from the 25th Infantry Division to the 4th Infantry Division (which had deployed to the Central Highlands in late 1966).