Augustus B. Farnham was born on March 10, 1839, in Bangor, Maine, to Henry and Harriet Farnham. His father was a city marshal. He grew up and attended school in Bangor, and by 1860, Farnham was working as a clerk.
On May 28, 1861, he received a commission as a 1st lieutenant in Company G of the 2nd Maine Infantry. He was promoted to captain on September 14, 1861. He mustered out on January 2, 1862, but on June 10, 1862, he became a major in the 16th Maine Infantry. He was promoted to lieutenant colonel on February 5, 1863, and then to colonel on April 1, 1865. The regiment took part in the Battle of Antietam, the Battle of Fredericksburg, the Battle of Chancellorsville, the Battle of Gettysburg, the Overland Campaign, the siege of Petersburg, and the Appomattox campaign. He was shot in the left lung in the Battle of Five Forks on April 1, 1865, and he mustered out on June 5, 1865.
Farnham returned to his parents’ household in Bangor after the war. By 1870, he was working as a deputy customs collector, and he owned $1,000 of personal property. He married Ardelia Clark in the early 1870s, and their daughter Mary was born around 1873. Ardelia died in the mid-1870s, and he married a woman named Mary around 1878. Their son Henry was born around 1879.
Farnham served as a postmaster for around 24 years. He also served two terms as sheriff of Penobscot County, and as adjutant general of Maine’s national guard. As one writer observed, he “was one of those who never lose their interest in city and state affairs.” He retired around 1906, and he died in Bangor of an “intestinal obstruction” on January 14, 1918.