HISTORY OF THE UNITS 

18th Century

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

An act of Congress on July 16, 1798 authorized twelve additional regiments of infantry.

An act of Congress of January 11, 1812 increased the Regular Army to 46 regiments of infantry and 4 of riflemen.

An act of Congress of March 3, 1815 reduced the Regular Army from the 46 infantry and 4 rifle regiments it deployed in the War of 1812 to a peacetime establishment of 8 infantry regiments, further reduced to 7 in 1821. The origins of the current Army regiment The numbering system dates from this act.

19th century

The Army was organized into seven infantry regiments, 1821;

1st infantry regiment

2nd infantry regiment

3rd infantry regiment

4th infantry regiment

5th infantry regiment

6th infantry regiment

7th infantry regiment

8th Infantry Regiment (added in 1838)

Ten one-year regiments were authorized by an act of Congress on 11 February 1847 due to the Mexican-American War, but only the 9th through 16th Infantry Regiments were activated; they were not permanently reformed until the 1850s and 1860s.

9th Infantry Regiment (U.S.) (added in 1855)

10th (U.S.) Infantry Regiment (attached 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 Congress of 28 July 1866 (14 Stat.332), the 2nd and 3rd Battalions of the existing 11th through 19th Infantry Regiments were expanded and designated as the 20th through 37th Infantry Regiments. Four new regiments (38th through 41st) were to be composed of black enlisted men, and the new 42nd through 45th Infantry Regiments for wounded Civil War veterans.

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, on March 15, 1869, with the 24th and 25th Infantry Regiments constituting the black enlisted force. On February 2, 1901, Congress passed the Army Reorganization Act, which authorized five additional regiments, 26th through 30th;

26th infantry regiment

27th infantry regiment

28th infantry regiment

29th infantry regiment

30th infantry regiment

20th Century

The Militia Act of 1903 standardized the regulations, organization, equipment, and training of the state militia force, forming the genesis of the modern National Guard (see Militia (United States) ).

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

31st Infantry Regiment

32nd Infantry Regiment

33rd Infantry Regiment

34th infantry regiment

35th infantry regiment

36th infantry regiment

37th infantry regiment

In 1917, a new numbering system was established. Infantry regiment numbers 1 through 100 were assigned to the Regular Army, 101 through 300 to the National Guard, and 301 and up to the National Army . 167 National Guard units were reorganized and numbered from the previously used state system to the new federal system; the 71st New York Infantry Regiment was able to press to keep its old 19th century number which violated this numbering rule while serving on the Mexican border in 1916; however, the unit was disbanded and most of its troops were assigned to the 27th Division after refederalization in 1917. [2]The 71st was reformed 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 former number as the 69th Infantry Regiment.

38th Infantry Regiment

39th Infantry Regiment

40th Infantry Regiment

41st Infantry Regiment

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