Kammala jumla mai zuwa: Bayan garrisoning Missouri don kaka da hunturu, 18th Indiana an haɗa shi da sojojin Grant da ke ƙoƙarin ƙetare Mississippi da kama Vicksburg. 18th Indiana ya yi yaƙi a
Port Gibson da Champion Hill kuma ya shiga cikin ayyukan kewaye da Vicksburg, inda ya umurci brigade da aka yaba don ayyukan da aka yi a lokacin da aka fara kai hari a kan sansanin soja a watan Mayu 1863. Bayan nasarar nasarar aikin Vicksburg, Brigade na Washburn ya kasance tare da XIII Army Corps da ke cikin ayyukan da ke kan Kogin Teche, da kuma nasarar nasarar da aka samu na 'yan tawaye da yawa. A watan Janairun 1864, an aika da Indiana na 18 zuwa Virginia inda ya shiga cikin rikice-rikice da yawa. A watan Agustan 1864, an haɗa Indiana na 18 zuwa Brigade na 4, 2nd Division (Grover) na Emory's XIX Army Corps.