Tuhia he tomokanga mō tēnei wāhanga - I muri i te hinganga o Wikitōria, i whakawhitihia te wehenga o Osterhaus ki Tennessee. I roto i te Campaign Chattanooga i awhina ia i a Maj. Gen. Joseph Hooker ki te hopu i te Maunga Tirohanga. I whai wāhi a Osterhaus ki te Campaign o Atlanta, engari na te mate mate mo te marama kotahi i ngaro ai ia i te Pakanga nui o Atlanta
He aha? Heoi, i hoki mai ia ki te whakahau me te whai waahi nui ki te Pakanga o Jonesborough. Whai muri i te hopu o Atlanta, i whakawhiwhia ki a ia te mana o te XV Corps, tetahi o nga roopu e wha i whakakotahihia ai te ope taua, i te Sherman's March to the Sea. I te Poutu-te-rangi 1865 i tohua a Osterhaus hei rangatira o nga kaimahi i te wehenga hoia o te Hauauru o Mississippi i raro i te whakahau a Maj. Gen. Edward Canby, he rangatira me te iti o te wheako whawhai i roto i te whakahau nui. I mahi a Osterhaus ki a Canby i roto i nga pakanga o Spanish Fort me Fort Blakely. I te wa i tukuna ai e Edmund Kirby Smith nga ope o te Rōpū ki te Whare Taonga o Trans-Mississippi, i tukuna a Osterhaus hei māngai mo Canby, na reira i hainatia e ia nga tuhinga mo te ope a te Uniana.