Eight companies which had been raised in Augusta, Maine were attached to the regiment in early 1864.

Upon their arrival they received four companies (the 31st, 32nd, 34th and 35th) which were to become attached to the regiment.

The 37th Field Artillery Battalion (attached to the regiment), arrived on 5 February.

About a week later four more companies of volunteer militia attached to the 20th regiment arrived, along with 20 horsemen acting as courier riders.

Keiser in this emergency attached the 2nd Engineer Combat Battalion to the regiment.

In 1941, Bleckwenn was called to active duty and attached to the 135th medical regiment.

Later, two additional companies were attached to the regiment, but no muster rolls for these companies have been located.

By the same decree the company of Mamluks was attached to the regiment.

The last reserve of the 352nd division, an engineer battalion, was attached to the 916th regiment in the evening.

Thirty black scouts, recruited in Southern Rhodesia, were also attached to the regiment.