Ulysses S. Grant's plan for late September 1864 was a two-pronged offensive. South of Petersburg, four divisions would try to cut the South Side Railroad - the operation that became the Battle of Peebles' Farm. North of the James River, Benjamin Butler's Army of the James would attack toward Richmond to keep Robert E. Lee from sending reinforcements south. Butler, often dismissed as a political general, devised what historian John Horn called his best plan of the war. Edward Ord's XVIII Corps would cross at Aiken's Landing and storm Fort Harrison, the strongest point in the Richmond defenses. David Birney's X Corps, augmented by Charles Paine's USCT division, would cross at Deep Bottom and take New Market Heights. The two prongs would converge on the inner Richmond works. Lee's Texas Brigade and the 3rd Arkansas - about 1,800 men - held the heights. They would face 13,000 Union troops, with USCT regiments in the first wave.

The first assault was repulsed. Confederate musketry from prepared positions tore the attacking brigade apart, and the field in front of the breastworks filled with the dead and wounded of the 4th, 6th, and 36th USCT regiments. It was during this attack that Sergeant Major Christian Fleetwood of the 4th USCT seized his regiment's colors after the bearers were shot down and carried them off the field - an act that would earn him the Medal of Honor. Birney reinforced and the men went forward again. Alfred Terry's division turned the Confederate left flank. Word reached the defenders that Fort Harrison had fallen, and John Gregg pulled his men back to Forts Gilmer and Gregg. The heights were taken. The cost was brutal: 850 Union casualties against only 50 Confederate. Most of those Union losses fell on the USCT regiments - on men who had every reason to know that capture meant murder or re-enslavement, and who went forward anyway.

The Medal of Honor citations from New Market Heights and Chaffin's Farm read like a roll call of quiet courage. Sergeant Major Fleetwood of the 4th USCT. Private James Gardiner of the 36th USCT, who shot a Confederate officer off the parapet and bayoneted him as the works were carried. Sergeant James H. Harris of the 38th USCT. Sergeant Major Thomas R. Hawkins of the 6th USCT, who rescued his colors. First Sergeant Alexander Kelly and Sergeant Major Milton M. Holland. First Sergeant Edward Ratcliff and Private William H. Barnes. Corporal Miles James, who continued to fight with one arm shattered, calling on his men to come forward. Sergeants Powhatan Beaty, Robert A. Pinn, Charles Veal. First Lieutenant Nathan H. Edgerton. Sergeant Decatur Dorsey. Three of the recipients - Edgerton, Hawkins, and Kelly, all of the 6th USCT - are depicted together in Don Troiani's painting Three Medals of Honor, unveiled in Philadelphia in 2013.

While the USCT were storming the heights, George Stannard's brigade of the XVIII Corps - veterans of Gettysburg - rushed Fort Harrison from the southeast. They took cover in a depression just below the fort, paused for breath, then carried it. Brigadier General Hiram Burnham was killed in the assault, and the Union troops promptly renamed the captured fort in his honor. Inside, things came apart: all three of Stannard's brigade commanders were down. Charles Heckman's supporting column veered too far north and was thrown back. Edward Ord himself was wounded trying to rally the troops. Confederate ironclads on the James added their guns to the chaos. The Union drive on Chaffin's Bluff stalled. When Lee learned Fort Harrison had fallen, he brought 10,000 men under Charles Field north from Petersburg overnight. His counter-attacks on September 30 were uncoordinated and easily repulsed, but the fort would remain Union for the rest of the war.

The fighting around Chaffin's Farm cost nearly 5,000 casualties. It did exactly what Grant intended: forced Lee to shift troops north, which helped the Union army to the south win at Peebles' Farm. After October the two armies settled into the trench warfare that would grind on until Appomattox. As of late 2021, the American Battlefield Trust and its partners had preserved 87 acres of the battlefield. The men who took New Market Heights wore the Butler Medal that Benjamin Butler personally commissioned for them - a private decoration he paid for himself, intended to mark what he believed the government had not properly recognized. He was right, and he was also early. The fourteen Medals of Honor from Chaffin's Farm represent something specific: an Army that, however reluctantly and however incompletely, had been forced by the men in front of it to see what they had done.