Mitchel was born in
Union County, Kentucky, but grew up in
Lebanon, Ohio. He was educated in Lebanon, and afterward at
West Point in 1825, where he was a classmate to
Robert E. Lee and
Joseph E. Johnston. He graduated in 1829, placing 15th out of 46 graduates. Mitchel stayed at West Point as assistant professor of mathematics for three years. After holding several military positions while studying law, he went to
Cincinnati, passed the
bar and became an attorney. He also filled the office of Chief Engineer of the
Little Miami Railroad, then in the process of construction. Subsequently, in 1836, he became assistant professor of mathematics, philosophy, and professor of
astronomy at
Cincinnati College, and during this incumbency achieved a national renown as an astronomical lecturer and builder of the
Cincinnati Observatory. He was instrumental in establishing the college's law school, and on his first vacation, surveyed and recommended the route of the planned Little Miami Railroad between Cincinnati and
Springfield, Ohio. Conceiving a desire to possess a fine
telescope, he began by striving to awaken interest in the subject of astronomy through a series of lectures. The first was heard by 16 people; but the last was listened to by an enraptured audience of 2,000. Availing himself of the enthusiasm thus generated, he organized the Cincinnati Astronomical Society with 300 members at $25 each, and started for Europe to find his telescope. His search was long, but successful and, returning, he plunged into the struggle to secure a suitable
observatory. In
Nicholas Longworth he found a helpful coadjutor. Upon the land which was donated by Longworth, located on the summit of
Mt. Adams. Mitchel began the foundation of his building and
John Quincy Adams, then more than 77 years of age, delivered an address at the laying of the cornerstone. At this period of undertaking, he had collected $3,000, and $6,500 necessary to complete his work. The subscriptions came in slowly and hence he collected them in person. Where money could not be procured, he took provisions that had
negotiable value, which he marketed and turned into cash. Many of his subscriptions being in work and materials no collectors would accept them as his assets and he undertook to make them available by buying all the materials, hiring all the men and superintending all the work. The ascent to the place of construction was steep. Therefore, he built a
kiln and burned the lime; he purchased a sand pit also and often shoveled its contents into the wagon with his own hands. He carried on with his classes, however, teaching five hours a day from eight until one. Each Saturday exhausted his funds and on Monday he had to begin collecting again. The construction was completed in March 1845, and he hoisted his telescope into place. At the time, it was the second-largest
refracting telescope in the world. There was no salary attached to the office of astronomer in this new observatory and Mitchel supported himself by
civil engineering on the route of the Ohio & Mississippi Railroad (
Ohio and Mississippi Railway) and by lecturing anywhere and everywhere. In 1853, he was elected as a member of the
American Philosophical Society. For a time, Cincinnati lost his inspirational presence. In 1859, Mitchel accepted the position of astronomer of the
Dudley Observatory in
Albany, New York, a position which he held until 1861, ==Civil War==