Infantry timelines · Infantry numbers 1–200

4th Infantry Regiment

A century of division assignments

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

4th Infantry Regiment unit graphic
4th Infantry Regiment
First division shown3d Infantry Division1 Oct 1917
Separate battalion histories3 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 15 Feb 1958; 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

3d Infantry Division25th Infantry Division71st Infantry Division10th Mountain Division102d 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 – 1 Oct 1917

    4th Infantry Regiment

    Assignment not established

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

    Source

  2. 1 Oct 1917 – 15 May 1940

    4th Infantry Regiment

    3d Infantry Division

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

    Source

    Deployments & overseas operations

    1. 1918

      France: Aisne, Champagne-Marne, Aisne-Marne, St. Mihiel and Meuse-Argonne

      4th Infantry Regiment · Campaign service

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

      Source
  3. 15 May 1940 – 1 Nov 1945

    4th Infantry Regiment

    No assigned division

    The cited record establishes service outside an assigned division. Higher headquarters and temporary operational attachments could still direct the unit.

    Source

    Deployments & overseas operations

    1. 1943

      Attu, Aleutian Islands

      4th Infantry Regiment · Deployment / overseas operation

      Fought in the Aleutian campaign as part of the force retaking Attu; the regiment was not then assigned to a division.

      Source
  4. 1 Nov 1945 – 31 Jan 1947

    4th Infantry Regiment

    25th Infantry Division

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

    Source

  5. 31 Jan 1947 – 1 Oct 1948

    4th 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

  6. 1 Oct 1948 – 10 Oct 1954

    4th Infantry Regiment

    No assigned division

    The cited record establishes service outside an assigned division. Higher headquarters and temporary operational attachments could still direct the unit.

    Source

  7. 10 Oct 1954 – 15 Sep 1956

    4th Infantry Regiment

    71st Infantry Division

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

    Source

  8. 15 Sep 1956 – 15 Feb 1958

    4th Infantry Regiment

    No assigned division

    The cited record establishes service outside an assigned division. Higher headquarters and temporary operational attachments could still direct the unit.

    Source

  9. 15 Feb 1958 – 2 Apr 1962

    1st Battle Group / Battalion lineage

    2d Infantry Brigade · Separate

    This headquarters is not a division. Temporary attachments in the service entries below are distinct from the formal assignment.

    Source

  10. 2 Apr 1962 – 5 Jun 1963

    1st 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. 5 Jun 1963 – 16 Dec 1987

    1st Battle Group / Battalion lineage

    3d Infantry Division

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

    Source

  12. 16 Dec 1987 – 16 Nov 1990

    1st 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

  13. 16 Nov 1990 – page cutoff*

    1st Battle Group / Battalion lineage

    Last documented: No assigned division

    The cited record establishes service outside an assigned division. Higher headquarters and temporary operational attachments could still direct the unit. 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. 2004

      Afghanistan

      1st Battle Group / Battalion lineage · Deployment / overseas operation

      Company A served in Afghanistan; this marker identifies a company deployment, not a deployment of the entire battalion.

      Source
  14. 15 Feb 1958 – 18 Apr 1963

    2d Battle Group / Battalion lineage

    3d Infantry Division

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

    Source

  15. 18 Apr 1963 – 3 Jun 1963

    2d Battle Group / Battalion lineage

    No assigned division

    The cited record establishes service outside an assigned division. Higher headquarters and temporary operational attachments could still direct the unit.

    Source

  16. 3 Jun 1963 – 21 Jul 1969

    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

  17. 21 Jul 1969 – 15 May 1991

    2d Battle Group / Battalion lineage

    No assigned division

    The cited record establishes service outside an assigned division. Higher headquarters and temporary operational attachments could still direct the unit.

    Source

  18. 15 May 1991 – 16 Jan 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

  19. 16 Jan 2005 – page cutoff*

    2d Battle Group / Battalion lineage

    Last documented: 10th Mountain 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. 2006-2007

      Afghanistan

      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.

      Source

    2. 2007-2009

      Baghdad, 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.

      Source
  20. 15 Feb 1958 – 1 Jun 1959

    3d 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

  21. 1 Jun 1959 – 31 Dec 1965

    3d Battle Group / Battalion lineage

    102d Infantry Division

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

    Source

  22. 31 Dec 1965 – 16 Oct 2009

    3d 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

  23. 16 Oct 2009 – 1 Oct 2012

    3d Battle Group / Battalion lineage

    170th Infantry Brigade · Separate

    This headquarters is not a division. Temporary attachments in the service entries below are distinct from the formal assignment.

    Source

  24. 1 Oct 2012 – 1 Nov 2012

    3d Battle Group / Battalion lineage

    Assignment not established

    The parent brigade inactivated during this month. A precise effective date for this battalion is not established here.

    Source

  25. 1 Nov 2012 – page cutoff*

    3d Battle Group / Battalion lineage

    Last documented: Inactive

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

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: 4th Infantry Regiment
  2. U.S. Army Center of Military History: 1st Battalion 4th Infantry Regiment
  3. U.S. Army Center of Military History: 2d Battalion 4th Infantry Regiment
  4. U.S. Army Center of Military History: 3d Battalion 4th Infantry Regiment
  5. U.S. Army: 170th Brigade inactivated in October 2012
  6. 4th 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.