90th 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.
First division shown20th Division (World War I)1 Oct 1918
Separate unit histories0 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. Battalion rows follow headquarters lineages, often descended from lettered companies, rather than assuming that the old regimental battalions continued unchanged.
The 1943 organization served briefly in the 10th Light Division. Sources differ between 13 and 22 February 1944 for its relief; that interval is left unresolved before replacement-training service.
Division patches
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.
At a glance
Assignments across time
Bar widths follow elapsed time.
Scroll horizontally on a small screen. Select a segment to open its dated entry. Diamond markers open deployments; their positions indicate the labeled year, not an exact start date or duration. Short assignments are easier to inspect in the list below.
- Division assignment
- 1st Infantry
- 2d Infantry
- 8th Infantry
- Separate headquarters
- Training / academy
- Inactive
- Unverified / last documented
Explore a date
Who were they with?
Look up the dated rows below. Service notes with incomplete dates are excluded; last-documented results do not certify a current assignment.
The dated record
Division timeline
No deployment with sufficiently established dates is plotted for this regiment. Read the assignment cards and service notes for its garrison, training and successor-unit history.
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.
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1 Jan 1916 – 31 Aug 1918
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31 Aug 1918 – 1 Oct 1918
90th Infantry Regiment
Assignment not established
The available record does not establish a precise assignment throughout this interval. No division is inferred.
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1 Oct 1918 – 28 Feb 1919
90th Infantry Regiment
20th Division (World War I)
Division names are normalized across historical redesignations. This entry follows the cited unit lineage.
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28 Feb 1919 – 13 Mar 1919
90th 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.
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13 Mar 1919 – 23 Mar 1919
90th Infantry Regiment
Assignment not established
The available record does not establish a precise assignment throughout this interval. No division is inferred.
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23 Mar 1919 – 10 Jul 1943
90th Infantry Regiment
Disbanded
The organization was removed from the rolls. A later reconstitution, if documented, is shown separately.
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10 Jul 1943 – 15 Jul 1943
90th Infantry Regiment
Inactive · 10th Mountain Division
The unit was inactive but retained the division assignment shown. Paper assignments and Reserve-officer training are not active combat service.
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15 Jul 1943 – 13 Feb 1944
90th Infantry Regiment
10th Mountain Division
Division names are normalized across historical redesignations. This entry follows the cited unit lineage.
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13 Feb 1944 – 23 Feb 1944
90th Infantry Regiment
Assignment not established
The available record does not establish a precise assignment throughout this interval. No division is inferred.
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23 Feb 1944 – 10 Aug 1945
90th Infantry Regiment
Training · No assigned division
Training service outside an established maneuver-division assignment. This label does not imply membership in the later TRADOC command.
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10 Aug 1945 – page cutoff*
90th Infantry Regiment
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.
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.
Patch artwork
Unmodified artwork from Wikimedia Commons; individual file pages identify the artist and license. Insignia represent the divisions, not regimental affiliation badges.
- 10th Mountain Division · file and credit · public domain
