When The Wolf Came: The Civil War and the Indian Territory by Mary Jane Warde was recently reviewed in the Civil War Book Review.
Excerpt:
After reading Warde’s book, I realize how little I knew. Here is the rich, full, and terrible story of the war’s impact not just on Indians who resided in Indian Territory (modern Oklahoma), but also those who resided throughout the American West. We learn of the heroic and tragic attempt by a Creek leader named Opothle Yahola to lead neutrals and Unionists—along with runaway slaves—to safety in Kansas at the outset of the war. Confederate forces—Texan units allied with American Indians from Indian Territory—attacked the party twice, finally scattering it to the winds. Many perished; some, including Yahola, straggled into Kansas utterly destitute and half-frozen, where even more suffering awaited. Preoccupied with the war effort in the East and often indifferent to Indians, the Union government failed to provide adequate supplies, leaving refugees to suffer through winter in the most miserable conditions imaginable, often without shelter, blankets, food, or medicine.
…
Warde’s book will stand for decades as the most comprehensive and thoughtful study of the Civil War’s impact on Indian Territory. To her credit, she doesn’t stick solely to the narrative of the war, but shows how the war helped give rise to massive relocations (ethnic cleansings) over the next several decades. At times, the books seems a bit too encyclopedic, but Warde makes a good case that even seemingly unrelated events—e.g., the Modoc War and the removal that followed—were precipitated by events in the 1860s.
You can read the full review at the Civil War Book Review.