Thunder Hawk, identified by ink inscription on the mount's lower front, is the subject of this cabinet card portrait made at Fort Sully in 1870, placing it among the earliest known studio photographs of Hunkpapa Lakota leaders taken at that post. No photographer's imprint is visible on the mount, though the image aligns with work produced at or near Fort Sully during the period when military-associated photographers documented visiting delegations. The subject is seated in a three-quarter pose with his gaze directed slightly upward and to the left, conveying a composed and deliberate bearing.

He wears a dark vest over a white collarless shirt, with a patterned trade cloth or blanket draped across his lap, and a beaded or wrapped ornament at his collar. Long straight hair falls past his shoulders, and a single feather with banded quilling rises prominently behind his head. His hands rest in his lap, holding a slender object, possibly a pipe stem or riding crop, and metal bracelets are visible at his wrists.

Thunder Hawk was a Hunkpapa Lakota man whose name appears in connection with the Oncpapa band, as written in pencil at the top of the reverse. Fort Sully, located along the Missouri River in present-day South Dakota, served as a key site for treaty negotiations and government-sponsored portrait sessions with Lakota leaders throughout the late 1860s and 1870s.

The reverse bears the inscription "Oncpapa" at the top, followed by "Our Indian Friends," "Fort Sully," and the date "1870," along with extensive penciled arithmetic calculations covering the remainder of the mount.

From the collection of James Lee Soffer