Alvan Cullem Gillem was a general in the Union Army during the American Civil War. Although Southern-born, he remained loyal to the Federal government and fought in several battles in the Western Theater before commanding occupation troops in Mississippi and Arkansas during Reconstruction. He later played a prominent role in the Modoc War in 1873.

The Modoc War, or the Modoc Campaign, was an armed conflict between the Native American Modoc people and the United States Army in northeastern California and southeastern Oregon from 1872 to 1873. Eadweard Muybridge photographed the early part of the US Army's campaign.