John Adams Dix (July 24, 1798 – April 21, 1879) was an American politician and military officer who was Secretary of the Treasury, Governor of New York and Union major general during the Civil War. He was notable for arresting the pro-Southern Maryland General Assembly, preventing that divided border state from seceding, and for arranging a system for prisoner exchange via the Dix–Hill Cartel, concluded in partnership with Confederate Major General Daniel Harvey Hill. Biography Dix was born in Boscawen, New Hampshire on July 24 1798, the son of Timothy Dix and Abigail Wilkins, and brother of composer Marion Dix Sullivan. He was educated at Phillips Exeter Academy, and joined the US Army as an ensign in May 1813, serving under his father until the latter's death a few months later. He attained the rank of captain in August 1825 and resigned from the Army in December 1828. In 1826, Dix married Catherine Morgan, the adopted daughter of Congressman John J. Morgan, who gave Dix a job overseeing his upstate New York land holdings in Cooperstown. Dix and his wife moved to Cooperstown in 1828, and he practiced law in addition to overseeing the land holdings. In 1830, he was appointed by Governor Enos T. Throop as Adjutant General of the New York State Militia, and moved to Albany, New York. He was Secretary of State of New York from 1833 to 1839, and a member of the New York State Assembly (Albany Co.) in 1842. U.S. Senator Dix was elected as a Democrat to the United States Senate to fill the vacancy caused by the resignation of Silas Wright, Jr., and held office from 1845 to 1849. In November 1848, he was the Barnburner/Free-Soil candidate for Governor of New York, but was defeated by Whig Hamilton Fish. In February 1849, he ran for re-election to the U.S. Senate as the Barnburners' candidate, but the Whig majority of the State Legislature elected William H. Seward. Railroad president and postmaster In 1853 Dix was president of the Mississippi and Missouri Railroad. He was appointed Postmaster of New York City and served from 1860 to 1861. In addition to his military and public duties, Dix was the president of the Union Pacific from 1863 to 1868 during construction of the First transcontinental railroad. He was the figurehead for rail baron Thomas C. Durant, in both of his railroad presidencies. He was also