The Third Brigade of the Tennessee Militia was absorbed into the National Guard of the United States on 25 March 1887 as the 3rd Infantry Regiment, with headquarters in Knoxville.

[2] On 3 July 1916, the 3rd Infantry Regiment was mustered into federal service at Nashville and deployed to Eagle Pass, Texas, to take part in the Army's pursuit of the Mexican bandit Francisco "Pancho" Villa along the Mexico-U.S. border.

On 3 August, the War Department ordered concentration and organization of the units designated to form the division at Camp Sevier, Greenville, South Carolina.

During October 1917, Selective Service men from Camps Gordon, Jackson and Pike completed the regiment and filled out the rest of the division.

[2] Affiliated with the British, 117th Infantry Regiment as part of the 30th Division reached the front lines for training on 16 July 1918 and remained until 18 August.

[2] During its advance of 20 miles (32 km), the 30th (US) Division captured 98 officers, 3,750 enlisted men, 72 pieces of artillery, 26 trench mortars and 426 machine guns.

[2] During this advance on 7 October 1918 Sergeant Edward R. Talley, from Russellville, Tennessee, Company L, 117th Infantry Regiment near Ponchaux, France, was undeterred by seeing several comrades killed in attempting to put a hostile machinegun nest out of action.

Sergeant Talley rushed the machinegun nest in the face of intense enemy fire, killed or wounded at least 6 of the crew, and silenced the gun.

When the enemy attempted to bring forward another gun and ammunition Sergeant Talley drove them back by effective fire from his rifle.

[2] The next day, Sergeant James Ernest Karnes from Knoxville, and Private Calvin John Ward from Morristown, Company D, 117th Infantry Regiment near Estrees, France, on 8 October 1918 were taking part in a general advance.

[2] The 117th Infantry moved back to the United States after the signing of the Armistice on 11 November 1918 and was demobilized during 13–17 April 1919 at Fort Oglethorpe, Georgia near Chattanooga.

The 117th Infantry Regiment arrived at the port of Charleston on 27 March 1919 on the troopship USS Pocahontas and was demobilized 17 April 1919 at Fort Oglethorpe, Georgia.

[2] After the Japanese attack on Pearl Harbor, the term of service of the regiment, along with the rest of the National Guard soldiers inducted in 1940-1941, was extended for the duration of the war.

The 117th Infantry Regiment moved back to Camp Blanding, Florida, by motor convoy on 28 February 1943 to conduct training designed to physically harden the troops.

From 6 April to 9 June 1944, the regiment was billeted in the town of Berkhamsted, England, and completed their final training before entering combat in Normandy.

They assaulted across the Vire-Taute Canal on 7 July 1944, establishing a bridgehead toward Les Landes, east of St Jean-de-Day, which the 3rd Armored Division passed through the regiment to conduct exploitation operations.

The plan called for saturation bombing by fighter-bombers, medium and heavy bombers from the front line back to the enemy's artillery positions to disorient and dislodge the Germans.

The 30th Infantry Division had made a spectacular attack, and opened the way for Patton's newly arrived Third Army to drive into Brittany and onward to Brest, France.

In the morning of 6 August 1944, the regiment moved southwest to the vicinity of Bracy, France near Mortain to relieve the 26th Infantry and to take up defensive positions.

En route, the regiment was stopped by an assistant division commander and diverted to Malmedy and Stavelot to block a powerful German counterattack.

It was estimated that at least 1000 German dead lined the bank of the Amblève River which was mute testimony to the heroic actions of the 1st battalion, 117th Infantry Regiment.

The regiment moved east on the morning of 18 April 1945 and by noon had closed on the Elbe River where they were ordered to set up a defense and wait for the Red Army.

On 27 May 1945 British troops occupied Magdeburg and the 117th Infantry moved 150 miles (240 km) south to Oelsnitz and Bad Elster, Germany near the Czechoslovakian border for occupation.

[2] On 1 September 1950, during the Korean War, the 278th RCT was ordered into active federal service at home stations and moved to Fort Devens, Massachusetts.

While conducting mobilization training at Camp Shelby, the three armored cavalry troops of each squadron were equipped with nine M1A1 Abrams main battle tanks, 13 M3A2 Bradley fighting vehicles, and two 120 mm mortar carriers.

[7] The 278th RCT took over from the 30th BCT, North Carolina, commanded by BG Danny Hickman on Christmas Eve 2004 at FOB Caldwell where the regimental headquarters was established.

Each squadron was assigned to a FOB (forward operating base) and detachments sent to other locations, with some performing convoy escort missions from Kuwait to Mosul.

This unit conducted checkpoints, convoy operations and provided security for the Naval Special Warfare EOD teams as well as Australian bomb squads.

The 278th acted as the convoy security element for the 13th ESC, and was tasked with the protection of retrograde activities and FOB closures from the Turkish border to Kuwait.

Robert D. West received a Purple Heart and Combat Action Badge for injuries sustained on 31 May 2010 while assigned to 2nd Platoon RFS/278 ACR on a return mission to Marez/Diamond.