86th 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 shown18th 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 World War II organization was constituted in November 1942. Its phased activation is shown as an uncertain interval. “10th Mountain” includes the division’s earlier Light and later Infantry designations.
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
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.
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1 Jan 1916 – 31 Jul 1918
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31 Jul 1918 – 1 Oct 1918
86th 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 – 13 Feb 1919
86th Infantry Regiment
18th Division (World War I)
Division names are normalized across historical redesignations. This entry follows the cited unit lineage.
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13 Feb 1919 – 25 Nov 1942
86th Infantry Regiment
Disbanded
The organization was removed from the rolls. A later reconstitution, if documented, is shown separately.
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25 Nov 1942 – 12 Dec 1942
86th 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.
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12 Dec 1942 – 2 May 1943
86th 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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2 May 1943 – 15 Jul 1943
86th 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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15 Jul 1943 – 27 Nov 1945
86th Infantry Regiment
10th Mountain Division
Division names are normalized across historical redesignations. This entry follows the cited unit lineage.
Deployments & overseas operations
1945
Italy
86th Infantry Regiment · Campaign service
Campaign participation is recorded in the cited history. The year label summarizes campaign service, not an exact overseas tour. The labeled service overlaps an assignment change and is listed only once; consult the following assignment cards as well.
Source
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27 Nov 1945 – 18 Jun 1948
86th 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.
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18 Jun 1948 – 1 Jul 1948
86th 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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1 Jul 1948 – 1 Jul 1957
86th Infantry Regiment
10th Mountain Division
Division names are normalized across historical redesignations. This entry follows the cited unit lineage.
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1 Jul 1957 – page cutoff*
86th 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
