References:
Dyer's Compendium of the War of the Rebellion, 1959 Edition, Volume 3, Page 997.

Notes: I have taken the liberty of reformatting some of the data, to eliminate the “Wall of Text” found in the original Compendium.

1st REGIMENT SIEGE ARTILLERY (AFRICAN DESCENT).

Organized at LaGrange, LaFayette and Memphis, Tenn., and Corinth, Miss., June 20, 1863. Attached to District of Corinth, 16th Army Corps, Dept. Tennessee, to November, 1863. Post of Corinth, 16th Army Corps, to January, 1864. Fort Pickering, District of Memphis, Tenn., 5th Division, 16th Army Corps, to April, 1864.

Served as Garrison at Corinth, Miss., till January, 1864, and at Fort Pickering, Memphis, Tenn., till March, 1864. 4 Cos., "A," "B," "C" and "D," Garrison at Fort Pillow, Tenn., and participated in the Massacre at that Post April 12, 1864.

Designation changed to 6th U. S. Colored Heavy Arty. March 11, 1864, and to 7th U. S. Colored Heavy Arty. April 26, 1864.