The Last Surrenders

On June 19, 1865, Principal Chief Peter P. Pitchlynn surrendered Choctaw Nation forces allied to the Confederacy to US Lt. Col. Asa Matthews. This took place in Doaksville, in southeastern Indian Territory, now an abandoned site near Fort Towson in Choctaw County, Oklahoma.
On June 23, the last Confederate general to give up his command, Stand Watie, rode into Doaksville and surrendered his Cherokee Nation and other forces to Matthews, including the First Indian Cavalry Brigade.
These surrenders did not involve the Indians being taken into custody but recognized the reinstitution of US government control, preliminary to more formal treaties.
Matthews, who had been an Illinois lawyer before the war, was acting under the authority of US Major General Francis Herron, commander of the Northern Division of Louisiana.

Herron had previously facilitated the surrender of the Confederate high command west of the Mississippi, including Simon Buckner. He is a major character  (and Buckner makes a brief appearance) in The Last Circle of Ulysses Grant.