45th 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 shownPhilippine Division22 Oct 1921
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 Scout heritage society dates the Bataan surrender to 9 April 1942; some secondary accounts give 10 April. The postwar 1st Battalion became the 77th Infantry (Philippine Scouts). The Philippine Division was subsequently named the 12th Infantry Division (Philippine Scouts).
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 – 1 Jun 1917
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1 Jun 1917 – 1 Jun 1919
45th 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 Jun 1919 – 22 Oct 1921
45th 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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22 Oct 1921 – 9 Apr 1942
45th Infantry Regiment
Philippine Division
Division names are normalized across historical redesignations. This entry follows the cited unit lineage.
Deployments & overseas operations
1941-1942
Philippine Islands
45th 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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9 Apr 1942 – 26 Mar 1946
45th Infantry Regiment
Surrendered · Captivity and surviving detachments
Organized resistance ended in surrender. Captivity and surviving detachments are not treated as normal divisional service or a formal inactivation order.
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26 Mar 1946 – 20 Dec 1948
45th Infantry Regiment
Philippine Division
Division names are normalized across historical redesignations. This entry follows the cited unit lineage.
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20 Dec 1948 – 10 Oct 1951
45th 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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10 Oct 1951 – page cutoff*
45th Infantry Regiment
Last documented: Disbanded
The organization was removed from the rolls. A later reconstitution, if documented, is shown separately. 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.
- Philippine Scouts Heritage Society: 45th Infantry
- 45th 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.
- Philippine Division · file and credit · public domain
