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

[3] Description/blazon A gold color metal and enamel device 1+1⁄16 inches (2.7 cm) in height overall consisting of a shield blazoned: Argent, a giant cactus Vert.

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 observing the situation for a few moments, Herman ordered an attack on the Mexican and German held hilltops overlooking the border town.

[5][6] 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.

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.

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.

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.

Moving through the rice paddies, the 25th occupied Umingan, Lupao, and San Jose and destroyed a great part of the Japanese armor on Luzon.

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.

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

Acting under United Nations orders, the Tropic Lightning Division moved from its base in Japan to Korea between 5–18 July 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.

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.

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

[9] From May through June 1970, the battalions of the 35th Infantry participated in the Incursion operations against enemy sanctuaries located in Cambodia, seizing thousands of tons of supplies and hundreds of weapons.

[9][verification needed] The 35th Infantry had three Medal of Honor recipients in Vietnam, Stephen Karopczyc, Ronald Eric Ray and Kenneth E.

[9] After its return to Schofield Barracks, the battalions of the 35th Infantry became a cadre unit due to the overall military downsizing and was part of a single brigade numbering 4,000 men.

The 35th Infantry trained for the next eight years throughout the Pacific Theater and continued to improve its combat capabilities with troop deployment varying in size from squads, who participated in training missions with Fijian forces, to exercises as large as Team Spirit, where more than 5,000 divisional troops and 1700 pieces of equipment were airlifted to South Korea for this annual exercise.

The four primary characteristics of this new light infantry division were to be: mission flexibility, rapid deployment and combat readiness at 100 percent strength with a Pacific Basin orientation.

[9] The 35th Infantry units did not participate in Operation Desert Storm, due to the 25th Division being earmarked for Pacific contingencies, such as a renewal of hostilities in Korea.

As a major ground reserve force for the U.S. Pacific Command, the "Tropic Lightning" Division routinely deploys from Schofield Barracks to participate in exercises in Japan, Korea, Thailand, Indonesia, the Philippines, Australia and the Big Island of Hawaii.

[9] Also, the term "regiment," dropped at the onset of the Pentomic (battle group) era in the late 1950s, began to be used again for units such as the 35th.

[9] From March 2011–March 2012, the 35th Infantry Regiment was deployed to RC East, Afghanistan in support of Operation Enduring Freedom.