20th Infantry Regiment Battalions

Modern Era, United States, Infantry

This second-pass battalion page ties each battalion icon more directly to the parent regiment's established story. Until a battalion-by-battalion lineage research pass is completed, the copy below should be read as regiment-specific context rather than as a final battalion lineage sheet.

1st Battalion, 20th Infantry Regiment icon
1st Battalion

1st Battalion, 20th Infantry Regiment

This entry now anchors the battalion page in the regiment's origin or defining early identity, giving the 1st Battalion slot a more specific historical frame than the first scaffold pass.

The 20th Infantry Regiment originated in the Civil War as the 2d Battalion of the 11th Infantry and became a separate regiment in the 1866 postwar reorganization of the Regular Army. It then passed through the familiar sequence of frontier service, western posts, and late nineteenth-century overseas campaigning that shaped many old line infantry regiments. Its special designation, "Sykes' Regulars," linked it to the professional Regular Army tradition from which it emerged.

2d Battalion, 20th Infantry Regiment icon
2d Battalion

2d Battalion, 20th Infantry Regiment

The 2d Battalion entry uses the regiment's middle or operational arc to give the page a clearer sense of how the parent unit developed over time.

Vietnam-era service came through battalion and separate company deployments rather than through the regiment as a whole. The 1st Battalion deployed in 1967 with the 11th Infantry Brigade, while Company E served as a long-range patrol and security element under higher commands that included I Field Force and the 4th Infantry Division. That battalion-level service included the regiment's darkest notoriety through the My Lai massacre, which involved Company C, 1st Battalion, 20th Infantry.

3d Battalion, 20th Infantry Regiment icon
3d Battalion

3d Battalion, 20th Infantry Regiment

The 3d Battalion entry now carries the regiment into its later or enduring modern identity, tightening the page around the way the lineage is remembered in the modern Army.

In the late Cold War and after, the regiment's battalions served in Panama, Korea, and the Stryker force. The 5th Battalion, 20th Infantry served with the 2nd Infantry Division in Korea and later became part of the Stryker structure at Joint Base Lewis-McChord, linked to the 2nd Infantry Division. The regiment's twentieth-century history therefore moved from the 2d Division interwar years to the 6th Division in World War II, then to brigade- and battalion-level service in Vietnam and Korea.

Research note: This second pass replaces the generic scaffold text with regiment-specific context drawn from the parent regiment page. Dedicated battalion-level lineage research is still deferred to a later pass.

See Also

  • 20th Infantry Regiment
  • Infantry Regiment Index
  • Modern Era