Tuhia he tohutoro mō tēnei wāhanga - I te mahi ture ia i Warm Springs, Virginia i te tīmatanga o te Pakanga ā-Iwi o Amerika. I uru atu ia ki te ope taua o te Rōpū o te Rōpū o te Rōpū 13 o Virginia i te marama o Mei 1861. I riro ia hei koroneela o te ope i muri i te Pakanga o Chancellorsville i te Mei 15, 1863. I te Mei 30, 1864, i mate ia i te pakanga i Totopotomoy Creek
Ko te Pakanga o Bethesda Church, i mua tonu i te Pakanga o Cold Harbor i te pakanga o Overland. Kua tohua a Terrill ki te taumata o te rangatira. I whakapumautia e te Kaunihera o te Kaunihera i muri i tana matenga i te Mei 31, 1864, kia eke mai i te Pipiri 1, 1864.