Farnsworth received the country's highest award for bravery during combat, the Medal of Honor, for his action during the Battle of Trevilian Station at Trevilian Station in Virginia on 11 June 1864.

By June 1864, the time of his meritorious action, he was the regiment's Sergeant Major.

[3] Farnsworth died on 4 July 1908 and his remains are interred at the Pomeroy City Cemetery in Washington.

The President of the United States of America, in the name of Congress, takes pleasure in presenting the Medal of Honor to Sergeant Major Herbert E. Farnsworth, United States Army, for extraordinary heroism on 11 June 1864, while serving with 10th New York Cavalry (Porter Guard), in action at Trevilian Station, Virginia.

Sergeant Major Farnsworth voluntarily carried a message which stopped the firing of a Union battery into his regiment, in which service he crossed a ridge in plain view and swept by the fire of both armies.