| Unit Name: | 6th Ohio Infantry Regiment |
| Country: | United States |
| Allegiance: | Union |
| Type: | Infantry |
| Branch: | Volunteer Army, American Civil War |
| Dates: | 1862 - 1864 |
| Size: | ~1,000 soldiers at outset of the war |
| Battles: | American Civil War |
| Notable Commanders: | Nicholas Longworth Anderson |
The 6th Ohio Infantry Regiment was a regiment in the Union Army during the American Civil War, primarily serving in the Western Theater in a series of campaigns and battles.
The 6th Ohio Infantry Regiment was organized in southwestern Ohio in the spring of 1861, formed around a nucleus independent militia unit known as the Guthrie Greys. It was mustered into Federal service on May 12. Most of its recruits were from Hamilton County and surrounding areas. Colonel and first Commander was William K. Bosley and Nicholas Longworth Anderson of Cincinnati was its first lieutenant colonel. Anderson served as colonel of the regiment during its last two years of service. The 6th was first sent to western Virginia before mustering out when its initial three-months term of enlistment expired. Reorganized as a three-years regiment, the regiment spent the next three years in the Western Theater before being mustered out on June 23, 1864.
On March 13, 1865, Anderson was brevetted to the rank of major general and brigadier general, for "gallant conduct and meritorious services in the Battle of Stone's River, Dec. 31, 1862" and for "distinguished gallantry and meritorious conduct in the Battle of Chickamauga, Sept. 19 and 20, 1863".
The lineage and history of the 6th Ohio Infantry Regiment was carried on by the 147th Infantry Regiment during World War I as part of the 37th Division, and during World War II as a separate unit. The unit continued as the 1st Battalion, 147th Armor (Ohio Army National Guard) until that unit's reorganization in 2007.