Although this flag is known as the George Rogers Clark Flag, it was not actually carried by Colonel Clark. The flag was designed in 1778 by Captain Leonard Helm, commander of the garrison holding Fort Sackville at Vincennes in the present-day state of Indiana. A Madame Goderre sewed the flag for Captain Helm; receipts for the material and Madame Goderre's labor was recorded on 12 November 1778. Helm was forced to surrender the fort to the British troops under Lieutenant Governor Henry Hamilton on 17 December 1778. Shortly thereafter, George Rogers Clark arrived at Vincennes on 23 February 1779, and recaptured the fort for the Americans. The red and green striped flag would not have been flying over Fort Sackville upon Clark's arrival, since the British were then in control of the fort, but it would have been in the possession of Helm's troops.
The fact that George Rogers Clark was more well known than the garrison commander, Captain Helm, probably accounts for the association of Clark's name with this flag. It is possible, though, that Colonel Clark might have actually used the flag during his assault on Fort Sackville if he assimilated Helm's troops into his own forces.