Ka dib markii uu Missouri ku wareejiyay xilliga dayrta iyo jiilaalka, 18th Indiana waxaa lagu daray ciidanka Grant ee isku dayaya inay ka gudbaan Mississippi oo ay qabsadaan Vicksburg. Guutada 18aad ee Indiana waxay ku dagaalameen Port Gibson
iyo Champion Hill wuxuuna ka qeyb qaatay howlgallada go'doominta ee ku xeeran Vicksburg, halkaas oo uu ku amray guuto lagu ammaanay ficillada geesinimada leh intii lagu jiray duulaankii ugu horreeyay ee qalcadda cadowga bishii May 1863. Kadib markii uu guul ku dhammaaday howlgalkii Vicksburg, guutada Washburn waxay la joogtay Ciidanka XIII ee ka qayb qaatay howlgallada ilaa Webiga Teche, iyo qabsashada guusha ee dhowr qalcadood oo ka tirsan Jabhadda. Bishii Janaayo 1864, 18th Indiana waxaa loo diray Virginia halkaas oo ay ka qeyb qaadatay dhowr dagaal oo adag. Bishii Agoosto 1864, 18th Indiana waxaa lagu daray Guutada 4aad, Qaybta 2aad (Grover) ee Emory's XIX Army Corps.