Most people consider that the surrender of Robert E. Lee at Appomattox Court House was the end of the Civil War, but sporadic fighting went on after that. The forces in the western part of the Confederacy (Trans-Mississippi Department in the vernacular of the day, which means beyond the Mississippi) was the last organized military force of the Confederacy. The Surrender of Gen. E. Kirby Smith.
With the surrender of these forces, the war was effectively over. (The portrait of Gen. Kirby is from the Library of Congress. Click the image for a larger view.)
The Battle for Appomattox Court House was April 9th of 1865, and Lee surrendered that afternoon. But in the west, the Confederacy fought on. Part of the reason was the difficulty in communications. The final surrender was probably the CSS Shenandoah (a commerce raider) which learned of the end of the war in August, but decided to sail to Liverpool to surrender to the British. They lowered their colors on November 6, 1865. The last Confederate General to surrender was Cherokee Brigadier General Stand Watie commanding the Confederate Indians. (He surrendered on June 23rd.)
The war’s last land fight occurred on May 12-13th at Palmitto Ranch, where 350 Confederates, under Col. John S. Ford, scored a victory over 800 overconfident Federals under Col. Theodore H. Barrett. But afterward the Confederates learned that Richmond had fallen and Gen. Robert E. Lee had surrendered more than a month earlier. The news devastated their morale, and they abandoned their lines.
The surrender was formalized on May 26th, under similar terms to those that Grant gave to the Army of Northern Virginia. Officers and troops were offered parole, given they would not take up arms against the US government again. Officers could keep their sidearms, horses and personal belongings. Horses belonging to the enlisted could also go home with their owners. Small arms, artillery, gunboats, etc. were all to be surrendered. Major General Edward Canby commanding the Military Division of Western Mississippi accepted the surrender in Shreveport, Louisiana.
Not all of the Trans-Mississippi Confederates went home. Some 2,000 fled into Mexico; most of them went alone or in squad-sized groups, but 1 body numbered 300. With them, mounted on a mule, wearing a calico shirt and silk kerchief, sporting a revolver strapped to his hip and a shotgun on his saddle, was Smith.
The article from the New York Times that carried the news can be found at the following link. The Surrender of Kirby Smith.; IMPORTANT ORDER BY GEN. CANBY. HEADQUARTERS MILITARY DIVISION WEST MISSISSIPI,