Infantry timelines · Infantry numbers 1–200

55th Infantry Regiment

A century of division assignments

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

55th Infantry Regiment unit graphic
55th Infantry Regiment
First division shown7th Infantry Division16 Nov 1917
Separate unit 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 20 Sep 1943; 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.

The armored successor rows cover formation through the end of the European war on 8 May 1945. Their closing boundary is a coverage limit, not an inactivation date; later service is not established here.

Division patches

7th Infantry Division11th Armored 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 – 15 May 1917

    55th Infantry Regiment

    Not yet constituted / organized

    This timeline begins in 1916. The cited organization had not yet been constituted or organized during this interval; its formation follows.

    Source

  2. 15 May 1917 – 16 Nov 1917

    55th Infantry Regiment

    Assignment not established

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

    Source

  3. 16 Nov 1917 – 22 Sep 1921

    55th Infantry Regiment

    7th Infantry Division

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

    Source

    Deployments & overseas operations

    1. 1918

      Lorraine

      55th Infantry Regiment · Campaign service

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

      Source
  4. 22 Sep 1921 – 31 Jul 1922

    55th 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

  5. 31 Jul 1922 – 9 Jun 1942

    55th Infantry Regiment

    Disbanded

    The organization was removed from the rolls. A later reconstitution, if documented, is shown separately.

    Source

  6. 9 Jun 1942 – 15 Aug 1942

    55th Infantry Regiment

    Inactive · 11th Armored Division

    The unit was inactive but retained the division assignment shown. Paper assignments and Reserve-officer training are not active combat service.

    Source

  7. 15 Aug 1942 – 20 Sep 1943

    55th Infantry Regiment

    11th Armored Division

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

    Source

  8. 20 Sep 1943 – 9 May 1945

    21st Armored Infantry Battalion · Predecessor

    11th Armored Division

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

    Source

    Deployments & overseas operations

    1. 1944-1945

      Western Europe

      21st Armored Infantry Battalion · Predecessor · Deployment / campaign service

      Served in the 11th Armored Division during its European campaign. The division arrived in France in December 1944 and entered Germany in March 1945. The labeled service overlaps an assignment change and is listed only once; consult the following assignment cards as well.

      Source
  9. 20 Sep 1943 – 9 May 1945

    55th Armored Infantry Battalion · Predecessor

    11th Armored Division

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

    Source

    Deployments & overseas operations

    1. 1944-1945

      Western Europe

      55th Armored Infantry Battalion · Predecessor · Deployment / campaign service

      Served in the 11th Armored Division during its European campaign. The division arrived in France in December 1944 and entered Germany in March 1945. The labeled service overlaps an assignment change and is listed only once; consult the following assignment cards as well.

      Source
  10. 20 Sep 1943 – 9 May 1945

    63d Armored Infantry Battalion · Predecessor

    11th Armored Division

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

    Source

    Deployments & overseas operations

    1. 1944-1945

      Western Europe

      63d Armored Infantry Battalion · Predecessor · Deployment / campaign service

      Served in the 11th Armored Division during its European campaign. The division arrived in France in December 1944 and entered Germany in March 1945. The labeled service overlaps an assignment change and is listed only once; consult the following assignment cards as well.

      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. ETO Theater Historian: 11th Armored Division order of battle, reproduced by EUCMH
  2. 55th 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.