Hugh Buchanon was born in Argyll and Bute, Scotland in 1823. He immigrated to the United States in 1836, becoming Naturalized in Orleans County, Vermont. He studied law and was admitted to the bar in 1845. The following year, he set up his law practice in Newnan, Georgia. In 1847, he married Mary Owen in Coweta County, Georgia.

Buchanon was elected to the Georgia Senate in 1855 and 1857, served as a delegate Democratic National Conventions in 1856 and 1868 and as a presidential elector on the Democratic ticket of Breckinridge and Lane in 1860. During the Civil War, Buchanon enlisted in the Confederate Army and served from June 1861 until 1865. After the war, he was appointed as a judge of the Superior Court (Coweta circuit), serving from 1872 to 1880. He was also elected to the United States Congress, serving from March 4, 1881-March 3, 1885.

Hugh Buchanon died in Newnan on June 11, 1890 and is buried at Oak Hill Cemetery in Newnan, Coweta County, Georgia.