Infantry Branch (United States)

18th century

On 3 March 1791, Congress added to the Army "The Second Regiment of Infantry"

• The Act of 16 July 1798, authorized twelve additional regiments of infantry
• an Act of Congress on 11 January 1812, increased the regular army to 46 infantry and 4 rifle regiments
• an Act of Congress on 3 March 1815, which reduced the Regular Army from the 46 infantry and 4 rifle regiments it fielded in the War of 1812 to a peacetime establishment of 8 infantry regiments (reduced to 7 in 1821). The Army's current regimental numbering system dates from this act.

19th century

Army organized into seven infantry regiments, 1815;

• 1st Infantry Regiment
• 2nd Infantry Regiment
• 3rd Infantry Regiment
• 4th Infantry Regiment
• 5th Infantry Regiment
• 6th Infantry Regiment (later converted to an armored infantry regiment in the 1st Armored Division)
• 7th Infantry Regiment
• 8th Infantry Regiment (added in 1838)

Ten one-year regiments were authorized by the Act of 11 February 1847, due to the Mexican–American War, but only the 9th–16th Infantry Regiments were activated; they did not re-form permanently until the 1850s and 1860s.

• 9th Infantry Regiment (United States) (added in1855)
• 10th Infantry Regiment (United States) (added in 1855)

Civil War expansion to 19 regiments;

• 11th Infantry Regiment
• 12th Infantry Regiment
• 13th Infantry Regiment
• 14th Infantry Regiment
• 15th Infantry Regiment
• 16th Infantry Regiment
• 17th Infantry Regiment
• 18th Infantry Regiment
• 19th Infantry Regiment

In a major expansion under General Order 92, War Department, 23 November 1866, pursuant to an act of 28 July 1866 (14 Stat. 332), the 2nd and 3rd battalions of the existing 11th-19th Infantry Regiments were expanded and designated the 20th–37th Infantry Regiments, with four new regiments (the 38th–41st) to be composed of black enlisted men, and the new 42nd-45th Infantry Regiments for wounded veterans of the Civil War.

• 20th Infantry Regiment
• 21st Infantry Regiment
• 22nd Infantry Regiment
• 23rd Infantry Regiment
• 24th Infantry Regiment
• 25th Infantry Regiment

This was reduced by consolidation to 25 regiments under General Order 17, War Department, 15 March 1869, with the 24th and 25th Infantry Regiments constituting the black enlisted force. On 2 February 1901, Congress passed the Army Reorganization Act, which authorized five additional regiments, the 26th-30th;

• 26th Infantry Regiment
• 27th Infantry Regiment
• 28th Infantry Regiment
• 29th Infantry Regiment
• 30th Infantry Regiment

20th century

The Militia Act of 1903 consolidated most state militia forces into the National Guard.

In 1916 Congress enacted the National Defense Act and under War Department General Orders Number 22 dated 30 June 1916 that ordered seven new regiments to be organised; four in the Continental United States, one in the Philippine Islands (31st Infantry Regiment (United States), one in Hawaii (32nd Infantry Regiment (United States), and one, the 33rd Infantry, in the Canal Zone.

• 31st Infantry Regiment
• 32nd Infantry Regiment
• 33rd Infantry Regiment
• 34th Infantry Regiment
• 35th Infantry Regiment
• 36th Infantry Regiment (later converted to an armored infantry regiment in the 3rd Armored Division)
• 37th Infantry Regiment

In 1917 a new numbering system was set up. Infantry regiments 1–100 were to be assigned to the Regular Army, 101–300 to the National Guard, and 301 and up to the National Army. 167 National Guard units were re-numbered from the previously-used state system to the new federal system; the 71st New York infantry regiment was able to lobby to keep their old 19th century number which violated this numbering rule while serving on the Mexican border in 1916; however, the unit was broken up and most of its troops assigned to the 27th Division after re-federalization in 1917.^[1] The 71st was re-formed in 1919 and served in World War II as the 71st Infantry Regiment. In the 1990s the 165th Infantry Regiment (formerly the 69th New York Infantry Regiment) reverted to its old number as the 69th Infantry Regiment.

• 38th Infantry Regiment
• 39th Infantry Regiment
• 40th Infantry Regiment
• 41st Infantry Regiment (later converted to an armored infantry regiment in the 2nd Armored Division)
• 42nd Infantry Regiment
• 43rd Infantry Regiment (reorganized in April 1921 as a Philippine Scouts unit)
• 44th Infantry Regiment (reorganized in April 1921 as a Philippine Scouts unit)
• 45th Infantry Regiment (reorganized in April 1921 as a Philippine Scouts unit)
• 46th Infantry Regiment (elements later converted to an armored infantry battalion in the 5th Armored Division)
• 47th Infantry Regiment
• 48th Infantry Regiment (elements later converted to an armored infantry battalion in the 7th Armored Division)
• 49th Infantry Regiment (elements later converted to an armored infantry battalion in the 8th Armored Division)
• 50th Infantry Regiment (elements later converted to an armored infantry battalion in the 6th Armored Division)
• 51st Infantry Regiment (elements later converted to an armored infantry battalion in the 4th Armored Division)
• 52nd Infantry Regiment (elements later converted to an armored infantry battalion in the 9th Armored Division)
• 53rd Infantry Regiment
• 54th Infantry Regiment (elements later converted to an armored infantry battalion in the 10th Armored Division)
• 55th Infantry Regiment (elements later converted to an armored infantry battalion in the 11th Armored Division)
• 56th Infantry Regiment (elements later converted to an armored infantry battalion in the 12th Armored Division)
• 57th Infantry Regiment (reorganized in April 1921 as a Philippine Scouts unit)
• 58th Infantry Regiment
• 59th Infantry Regiment (elements later converted to an armored infantry battalion in the 13th Armored Division)
• 60th Infantry Regiment
• 61st Infantry Regiment
• 62nd Infantry Regiment (elements later converted to an armored infantry battalion in the 14th Armored Division)
• 63rd Infantry Regiment
• 64th Infantry Regiment
• 65th Infantry Regiment (reorganized by the Reorganization Act of 4 June 1920 from the Puerto Rico Regiment)
• 66th Infantry Regiment (later converted to an armored regiment in the 2nd Armored Division)
• 67th Infantry Regiment (later converted to an armored regiment in the 2nd Armored Division)
• 68th Infantry Regiment (elements converted to a tank battalion in the 6th Armored Division)
• 69th Infantry Regiment (designated as 165th Infantry Regiment 1917–1992)
• 70th Infantry Regiment
• 71st Infantry Regiment (briefly existed in 11th Division in WWI)
• 71st New York Infantry Regiment (unit broken up after federalization; most troops served in 27th Division in WWI, went on to serve as 71st Infantry in WWII)
• 72nd Infantry Regiment
• 73rd Infantry Regiment
• 74th Infantry Regiment (redesignated from 474th Infantry Regiment in 1954)
• 75th Infantry Regiment
• 75th Ranger Regiment (uses the number of the 75th Infantry Regiment, but does not carry on its lineage)
• 76th Infantry Regiment
• 77th Infantry Regiment (Philippine Scouts)
• 78th Infantry Regiment (Philippine Scouts)
• 79th Infantry Regiment (Philippine Scouts)
• 80th Infantry Regiment
• 81st Infantry Regiment
• 82nd Infantry Regiment
• 83rd Infantry Regiment
• 84th Infantry Regiment
• 85th Infantry Regiment (mountain infantry unit during World War II; called the 85th Mountain Infantry Regiment for a portion of its service)
• 86th Infantry Regiment (mountain infantry unit during World War II; called the 86th Mountain Infantry Regiment for a portion of its service)
• 87th Infantry Regiment (mountain infantry unit during World War II; called the 87th Mountain Infantry Regiment for a portion of its service)
• 88th Infantry Regiment
• 89th Infantry Regiment
• 90th Infantry Regiment
• 91st Infantry Regiment
• The 92nd through 100th Infantry Regiments were never constituted

A new system, the U.S. Army Combat Arms Regimental System, or CARS, was adopted in 1957 to replace the old regimental system. CARS uses the Army's traditional regiments as parent organizations for historical purposes, but the primary building blocks are divisions, and brigade became battalions. Each battalion carries an association with a parent regiment, even though the regimental organization no longer exists. In some brigades several numbered battalions carrying the same regimental association may still serve together, and tend to consider themselves part of the traditional regiment when in fact they are independent battalions serving a brigade, rather than a regimental, headquarters. The CARS was replaced by the U.S. Army Regimental System (USARS) in 1981.

21st century

There are exceptions to USARS regimental titles, including the Armored Cavalry Regiments and the 75th Ranger Regiment created in 1986. On 1 October 2005, the word "regiment" was formally appended to the name of all active and inactive CARS and USARS regiments. So, for example, the 1st Cavalry officially became titled the 1st Cavalry Regiment

Branch plaque

The plaque design has the branch insignia, letters and border in gold. The background is Saxony blue.

Regimental insignia

Personnel assigned to the Infantry branch affiliate with a specific regiment and wear the insignia of the affiliated regiment.

Regimental coat of arms

There is no standard infantry regimental flag to represent all of the infantry regiments. Each regiment of infantry has its own coat of arms which appears on the breast of a displayed eagle. The background of all the infantry regimental flags is flag blue with yellow fringe.

Branch colors

Saxony Blue – 65014 cloth; 67120 yarn; PMS 5415.

The Infantry has made two complete cycles between white and light blue. During the Revolutionary War, white facings were prescribed for the Infantry. White was the color used for Infantry until 1851 at which time light or Saxony blue was prescribed for the pompon and for the trimming on Infantry horse furniture. In 1857, the color was prescribed as sky blue. In 1886, the linings of capes and trouser stripes were prescribed to be white. However, in 1902, the light blue was prescribed again. In 1917, the cape was still lined with light blue but the Infantry trouser stripes were of white as were the chevrons for enlisted men. The infantry color is light blue; however, infantry regimental flags and guidons have been National Flag blue since 1835. White is used as a secondary color on the guidons for letters, numbers, and insignia.

Birthday

14 June 1775. The Infantry is the oldest branch in the Army. Ten companies of riflemen were authorized by the Continental Congress Resolve of 14 June 1775. However, the oldest Regular Army Infantry Regiment, the 3rd Infantry, was constituted on 3 June 1784 as the First American Regiment.

Light Infantry

Primarily foot-mobile, usually transported by motorized assets, capable of air assault operations.

• Light Infantry: Standard light infantry not otherwise designated or qualified as one of the other three subtypes. Organized into battalions consisting of an Headquarters and Headquarters Company (HHC) and three rifle companies. Three light infantry battalions form the primary maneuver component of an Infantry Brigade Combat Team (Light).
• Airborne Infantry: Parachute qualified and capable of night, low-level parachute insertion when deployed by U.S. Air Force fixed-wing strategic or tactical transport aircraft or Army Aviation assets. Organized into battalions consisting of an HHC, three rifle companies, and an antiarmor company. Three airborne infantry battalions form the primary maneuver component of an Infantry Brigade Combat Team (Airborne).
• Air Assault Infantry: Assigned to units with associated Army Aviation elements, with both the infantry and aviation elements specifically trained and organized to perform the air assault mission, however all light infantry are capable of performing the air assault mission when transported by appropriate aviation assets. Organized into battalions consisting of an HHC, three rifle companies, and an antiarmor company. Three air assault infantry battalions form the primary maneuver component of an Infantry Brigade Combat Team (Air Assault).
• Ranger Infantry: Parachute qualified and specifically trained and designated for special operations missions as well as conventional light infantry tasks. Organized into battalions consisting of an HHC and three Ranger companies. The three Ranger infantry battalions form the primary maneuver component of the 75th Ranger Regiment.

Stryker Infantry

Equipped with M1126 Stryker Infantry Carrier Vehicles, "Stryker" infantry is essentially a new form of "medium infantry." While technically a form of mechanized infantry, because of their namesake wheeled mounts, they are more heavily armored and weapon equipped than light infantry but not as robust in either as mechanized infantry. Organized into battalions consisting of an HHC and three Stryker infantry companies. Three infantry battalions form the primary maneuver component of a Stryker Brigade Combat Team.

Mechanized Infantry

Equipped with M2 Bradley Infantry Fighting Vehicle, they are trained, organized, and equipped to operate in conjunction with tanks, therefore, essentially forming the modern equivalent of "heavy" or "armored" infantry. (Both terms, historically eschewed by the U.S. Army Infantry Branch due to supposed pejorative or "Armor Branch," viz., "tank unit" biases.) Mechanized infantry is organized into "Combined Arms" battalions consisting of an HHC, and either two tank companies, and one mechanized infantry company, or two mechanized infantry companies and one tank company. Three Combined Arms Battalions form the primary maneuver component of an Armored Brigade Combat Team.