Coburn was born in Indianapolis, Indiana, in 1825 (the year the city became the new state capital) and attended the public schools there. Later, he attended Wabash College in Crawfordsville, Indiana, graduating in 1846. As a student, he founded the Wabash College chapter of Beta Theta Pi fraternity, the first Greek letter fraternity on the campus and in continuous existence to today.[1][2] He studied law, was admitted to the bar in 1849, and commenced practice in Indianapolis.
He was captured in Kentucky and spent time in Libby Prison before being exchanged. Later, Coburn and Colonel Benjamin Harrison fought side by side in several battles while under General William Tecumseh Sherman's command. During that time, Coburn and his troops were the first into Atlanta and secured the city's surrender. There is a large marker in downtown Atlanta where the city's mayor surrendered the city to Coburn. He was mustered out on September 20, 1864.
He promoted the building of the Soldiers' and Sailors' Orphanage in Knightstown, Indiana, and he helped secure the use of land in Indianapolis for Garfield Park. His later years were spent living in the Bates-Hendricks House at 1526 S. New Jersey Street in Indianapolis with his wife Caroline (Test) Coburn until his death in 1908.
Congressional service
Coburn was appointed as the first secretary of the Territory of Montana in March 1865 but resigned at once. He was elected judge of the fifth judicial circuit of Indiana in October 1865 and resigned in July 1866. Later, he was elected as a Republican to the Fortieth and to the three succeeding Congresses (March 4, 1867 – March 3, 1875). While in Congress, he served as chairman of the Committee on Public Expenditures (41st Congress), and as a member of Committee on Military Affairs (42nd and 43rd Congresses). He was an unsuccessful candidate for reelection in 1874 to the 44th Congress.
After leaving Congress, he was appointed a justice of the Supreme Court of the Territory of Montana on February 19, 1884, and served until December 1885. He returned to Indianapolis, and resumed the practice of law. He died in Indianapolis on January 28, 1908, and was buried in Crown Hill Cemetery.
Welcher, Frank Johnson, and Larry G. Ligget. Coburn’s Brigade: The 85th Indiana, 33rd Indiana, 19th Michigan, and 22nd Wisconsin in the Western Civil War. Carmel, Ind.: Guild Press of Indiana, 1999.