Monument to the 16th OVI at Vicksburg Battlefield
Inscription reads:

SIXTEENTH INFANTRY
CAPT. ELI W. BOTSFORD,
MAJ. MILTON MILLS,
2d BRIG. 4th DIV. 13th CORPS.

Monument is located on Union Avenue, 100 yards south of the Iowa Memorial.

Image from National Park Service.

Monument to the 16th OVI marking assault of May 22, 1863, at Vicksburg Battlefield
Inscription reads:

(looking for better image so text can be read)

From nps.gov site:
In relation to the above monument, Also a marker designating the assault of 22 May 1863, located on the ridge 400 ft west of Union Avenue, southwest of the Old Reunion Grounds.

Image from National Park Service.