173d Infantry Regiment
Other branch / predecessor service
Lineage service in another branch or under a predecessor designation. This interval is not plotted as an infantry maneuver-division assignment.
First division shownNot establishedSee source notes
Separate unit histories1 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 11 Sep 2016; 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 1st Battalion was converted from 1st Squadron, 131st Cavalry, in September 2016. The 173d Infantry Regiment and the 173d Airborne Brigade are different organizations.
Division patches
Division names appear in the timeline. No verified patch artwork is included for these assignments.
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 – 11 Sep 2016
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11 Sep 2016 – page cutoff*
1st Battle Group / Battalion lineage
Last documented: 256th Infantry Brigade · Brigade assignment
This headquarters is not a division. Temporary attachments in the service entries below are distinct from the formal assignment. 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.
Service note · dates incomplete
1st Battle Group / Battalion lineage · Service and organization
The battalion serves in the 256th Infantry Brigade Combat Team. This brigade relationship does not imply assignment to the similarly numbered airborne brigade.
Sources and scope
Army Center of Military History lineage certificates, regimental associations and secondary histories document assignments, operations and battalions. Exact lineage dates and approximate historical coverage are distinguished. 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.
- Southeast Sun: 131st Cavalry becomes 173d Infantry, September 2016
- 256th Infantry Brigade and its battalions (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.