Infantry timelines · Infantry numbers 1–200

12th Infantry Regiment

A century of division assignments

1916–2026 · Regimental service, battle groups, battalions and deployments.

12th Infantry Regiment unit graphic
12th Infantry Regiment
First division shown8th Infantry Division17 Dec 1917
Separate battalion histories5 documented elementsDated lineages and service notes below
Page cutoff8 September 2026Last-documented status is explicitly marked

One regiment, separate assignments

The common row follows the regiment. After its reorganization, battle groups and battalions could hold different assignments at the same time. A deployment or temporary attachment does not by itself change the assigned division. The common row closes on 1 Apr 1957; later service belongs to the separate element rows. Battalion rows follow headquarters lineages, often descended from lettered companies, rather than assuming that the old regimental battalions continued unchanged.

Division patches

8th Infantry Division4th Infantry Division1st Infantry Division25th Infantry Division2d Infantry Division

Representative division patches. Patterns could change over time; an image does not imply that the exact version was worn throughout every period. Divisions without a verified asset remain identified by name.

The dated record

Division timeline

Battalion overview →

Deployments, operations and credited campaign service appear inside assignment cards. Award years establish credited service, not exact tour dates. Some service notes identify only company-sized elements. This is a sourced selection, not a complete movement log.

Assignment ends are exclusive: the next period starts on that date. *Striped final bars mean last documented, with later status unverified through the page cutoff. Unknown intervals are not treated as inactive.

  1. 1 Jan 1916 – 17 Dec 1917

    12th Infantry Regiment

    Assignment not established

    The available record does not establish a precise assignment throughout this interval. No division is inferred.

    Source

  2. 17 Dec 1917 – 15 Aug 1927

    12th Infantry Regiment

    8th Infantry Division

    Division names are normalized across historical redesignations. This entry follows the cited unit lineage.

    Source

  3. 15 Aug 1927 – 1 Oct 1933

    12th Infantry Regiment

    4th Infantry Division

    Division names are normalized across historical redesignations. This entry follows the cited unit lineage.

    Source

  4. 1 Oct 1933 – 10 Oct 1941

    12th Infantry Regiment

    8th Infantry Division

    Division names are normalized across historical redesignations. This entry follows the cited unit lineage.

    Source

  5. 10 Oct 1941 – 27 Feb 1946

    12th Infantry Regiment

    4th Infantry Division

    Division names are normalized across historical redesignations. This entry follows the cited unit lineage.

    Source

    Deployments & overseas operations

    1. 1944-1945

      Normandy, Northern France, Rhineland, Ardennes-Alsace and Central Europe

      12th Infantry Regiment · Campaign service

      Campaign participation is recorded in the Army lineage. The year label summarizes campaign service, not an exact overseas tour.

      Source
  6. 27 Feb 1946 – 15 Jul 1947

    12th Infantry Regiment

    Inactive

    The unit or its headquarters lineage was inactive. This status does not imply that every inherited honor or divisional affiliation was erased.

    Source

  7. 15 Jul 1947 – 1 Apr 1957

    12th Infantry Regiment

    4th Infantry Division

    Division names are normalized across historical redesignations. This entry follows the cited unit lineage.

    Source

  8. 1 Apr 1957 – 16 Dec 2004

    1st Battle Group / Battalion lineage

    4th Infantry Division

    Division names are normalized across historical redesignations. This entry follows the cited unit lineage.

    Source

    Deployments & overseas operations

    1. 1966-1970

      Vietnam

      1st Battle Group / Battalion lineage · Credited overseas service

      The Army lineage lists a unit decoration for service in these years. These are credited service years, not exact deployment and return dates.

      Source

    2. 2003-2004

      Iraq

      1st Battle Group / Battalion lineage · Credited overseas service

      The Army lineage lists a unit decoration for service in these years. These are credited service years, not exact deployment and return dates. The labeled service overlaps an assignment change and is listed only once; consult the following assignment cards as well.

      Source
  9. 16 Dec 2004 – page cutoff*

    1st Battle Group / Battalion lineage

    Last documented: 4th Infantry Division

    Division names are normalized across historical redesignations. This entry follows the cited unit lineage. The source establishes this last recorded status, not uninterrupted service through 2026. The striped bar extends to the page cutoff to keep the later research gap visible.

    Source

    Deployments & overseas operations

    1. 2005-2006

      Iraq

      1st Battle Group / Battalion lineage · Credited overseas service

      The Army lineage lists a unit decoration for service in these years. These are credited service years, not exact deployment and return dates.

      Source

    2. 2009-2010

      Afghanistan

      1st Battle Group / Battalion lineage · Credited overseas service

      The Army lineage lists a unit decoration for service in these years. These are credited service years, not exact deployment and return dates.

      Source
  10. 1 Apr 1957 – 1 Aug 1957

    2d Battle Group / Battalion lineage

    Inactive

    The unit or its headquarters lineage was inactive. This status does not imply that every inherited honor or divisional affiliation was erased.

    Source

  11. 1 Aug 1957 – 24 Mar 1959

    2d Battle Group / Battalion lineage

    8th Infantry Division

    Division names are normalized across historical redesignations. This entry follows the cited unit lineage.

    Source

  12. 24 Mar 1959 – 1 Oct 1963

    2d Battle Group / Battalion lineage

    1st Infantry Division

    Division names are normalized across historical redesignations. This entry follows the cited unit lineage.

    Source

  13. 1 Oct 1963 – 1 Aug 1967

    2d Battle Group / Battalion lineage

    4th Infantry Division

    Division names are normalized across historical redesignations. This entry follows the cited unit lineage.

    Source

    Deployments & overseas operations

    1. 1966-1970

      Vietnam

      2d Battle Group / Battalion lineage · Credited overseas service

      The Army lineage lists a unit decoration for service in these years. These are credited service years, not exact deployment and return dates. The labeled service overlaps an assignment change and is listed only once; consult the following assignment cards as well.

      Source
  14. 1 Aug 1967 – 17 Apr 1971

    2d Battle Group / Battalion lineage

    25th Infantry Division

    Division names are normalized across historical redesignations. This entry follows the cited unit lineage.

    Source

  15. 17 Apr 1971 – 1 Apr 1976

    2d Battle Group / Battalion lineage

    Inactive

    The unit or its headquarters lineage was inactive. This status does not imply that every inherited honor or divisional affiliation was erased.

    Source

  16. 1 Apr 1976 – 21 Sep 1976

    2d Battle Group / Battalion lineage

    4th Infantry Division

    Division names are normalized across historical redesignations. This entry follows the cited unit lineage.

    Source

  17. 21 Sep 1976 – 16 Jun 1989

    2d Battle Group / Battalion lineage

    Inactive

    The unit or its headquarters lineage was inactive. This status does not imply that every inherited honor or divisional affiliation was erased.

    Source

  18. 16 Jun 1989 – 15 Sep 1995

    2d Battle Group / Battalion lineage

    4th Infantry Division

    Division names are normalized across historical redesignations. This entry follows the cited unit lineage.

    Source

  19. 15 Sep 1995 – 29 Sep 2005

    2d Battle Group / Battalion lineage

    Inactive

    The unit or its headquarters lineage was inactive. This status does not imply that every inherited honor or divisional affiliation was erased.

    Source

  20. 29 Sep 2005 – 16 Nov 2005

    2d Battle Group / Battalion lineage

    2d Infantry Division

    Division names are normalized across historical redesignations. This entry follows the cited unit lineage.

    Source

  21. 16 Nov 2005 – 16 Mar 2008

    2d Battle Group / Battalion lineage

    2d Infantry Division

    Division names are normalized across historical redesignations. This entry follows the cited unit lineage.

    Source

    Deployments & overseas operations

    1. 2006-2008

      Iraq

      2d Battle Group / Battalion lineage · Credited overseas service

      The Army lineage lists a unit decoration for service in these years. These are credited service years, not exact deployment and return dates. The labeled service overlaps an assignment change and is listed only once; consult the following assignment cards as well.

      Source
  22. 16 Mar 2008 – page cutoff*

    2d Battle Group / Battalion lineage

    Last documented: 4th Infantry Division

    Division names are normalized across historical redesignations. This entry follows the cited unit lineage. The source establishes this last recorded status, not uninterrupted service through 2026. The striped bar extends to the page cutoff to keep the later research gap visible.

    Source

Service note · dates incomplete

3d Battalion · Vietnam, Germany and Bosnia

Served in Vietnam with the 4th Infantry Division. Later service included the 1st Armored Division and Bosnia before inactivation in Germany in 1997.

Source

Service note · dates incomplete

4th Battalion · Vietnam and Bosnia

Served in Vietnam with the 199th Light Infantry Brigade. Later served with the 8th Infantry and 1st Armored Divisions and deployed to Bosnia before inactivation in 1997.

Source

Service note · dates incomplete

5th Battalion · Vietnam

Deployed with the 199th Light Infantry Brigade and was inactivated after returning to Fort Benning in October 1970.

Source

Sources and scope

Army Center of Military History lineage certificates provide the dated backbone. Regimental associations and secondary histories supplement individual operations and battalions. Where the evidence stops, the page says so. A page cutoff is not a claim that every unit directory was current on that date.

Earlier battalions are covered by common regimental service; separately dated lineages and substantiated later battalions receive their own rows or notes. A unit graphic alone is not evidence of a battalion assignment. Reserve, training and inactive organizations are distinguished from active combat units.

  1. U.S. Army Center of Military History: 12th Infantry Regiment
  2. U.S. Army Center of Military History: 1st Battalion 12th Infantry Regiment
  3. U.S. Army Center of Military History: 2d Battalion 12th Infantry Regiment
  4. 12th Infantry Regiment history (Wikipedia; secondary)

Patch artwork

Unmodified artwork from Wikimedia Commons; individual file pages identify the artist and license. Insignia represent the divisions, not regimental affiliation badges.