| Unit Name: | 397th Engineer Battalion |
| Country: | United States |
| Allegiance: | United States Army |
| Branch: | US Army Reserve |
| Dates: | 15 August 1942 – Present |
| Specialization: | Engineers |
| Size: | Battalion |
| Garrison: | Marina, California |
| Current Commander: | LTC Christopher Smiley |
| Current Commander Label: | Commander |
| Ceremonial Chief: | CSM Russell Moore |
| Ceremonial Chief Label: | Command Sergeant Major |
The 397th Engineer Battalion is a multi-role engineer battalion of the United States Army based in Marina, California. Activated 18 May 1959 at Eau Claire, the battalion traces its lineage back to World War II. It is a United States Army Reserve formation and is subordinate to the 301st Maneuver Enhancement Brigade at Joint Base Lewis McCord WA.
Constituted 5 May 1942 in the Army of the United States as the 2d Battalion, 353d Engineer Regiment
Activated 15 August 1942 at Camp White, Oregon, as the 2d Battalion, 353d Engineer General Service Regiment
Reorganized and redesignated 1 April 1944 as the 1393d Engineer Construction Battalion
Inactivated 28 February 1946 in Japan
Redesignated 6 February 1947 as the 397th Engineer Construction Battalion, and allotted to the Organized Reserves
Activated 19 February 1947 at Milwaukee, Wisconsin
(Organized Reserves redesignated 25 March 1948 as the Organized Reserve Corps; redesignated 9 July 1952 as the Army Reserve)
Inactivated 17 November 1950 at Milwaukee, Wisconsin
Redesignated 27 April 1959 as the 397th Engineer Battalion
Activated 18 May 1959 at Eau Claire, Wisconsin
Elements ordered into active military service in support of the War on Terror:
| Award | Year(s) | Notes | |
|---|---|---|---|
| Philippine Presidential Unit Citation | 1944–1945 | For service in the Pacific Theater | |
| Valorous Unit Award | 2003–2004 | 652nd Engineer Company, Operation Iraqi Freedom |