During the american civil war, the 54th massachusetts regiment is most noteworthy

During the American Civil War, the 54th Massachusetts regiment is most noteworthy for being entirely formed by African-American soldiers.

Explanation:

The 54th Massachusetts Infantry Regiment was the first regular military unit in US history that consisted entirely of African Americans, with the exception of officers. It was created in 1863 in order to strengthen the Army of the Union that was at war with the Confederacy, during the Civil War.