Robert Patterson | |
|---|---|
 A portrait depicting Patterson during the Mexican-American War | |
| Born | January 12, 1792 Strabane, County Tyrone, Ireland |
| Died | August 7, 1881 (aged 89) Philadelphia, Pennsylvania, U.S. |
| Place of burial | |
| Allegiance | United States Union |
| Service | Regular Army Union Army |
| Years of service | 1812–1815; 1846–1848; 1861 |
| Rank |  Major General |
| Commands | Pennsylvania Militia Army of the Shenandoah |
| Battles / wars | |
| Other work | cotton miller, writer |
Robert Patterson (January 12, 1792 – August 7, 1881) was an Irish-born American military officer who served as a United States Army major general during the Mexican–American War, and a Union Army major general during the American Civil War. During the Mexican-American War, he served as second in command to Winfield Scott and fought at the Siege of Veracruz and the Battle of Cerro Gordo.
At the start of the Civil War, he was 69 years of age and the oldest commissioned major-general. He served only three months due to his failure to attack Confederate general Joseph E. Johnston's troops after the Battle of Hoke's Run. This allowed Johnston to support P. G. T. Beauregard and give the Union Army their first defeat at the First Battle of Bull Run. He was widely blamed for the Union loss at Bull Run and defended his Civil War performance with his book, A Narrative of the Campaign in the Valley of the Shenandoah, in 1861, published in 1865.
He served as an officer in the Pennsylvania Militia and United States Army during the War of 1812 and as commander of the Pennsylvania Militia during the Philadelphia nativist riots. He was politically active in Pennsylvania as a Jacksonian Democrat. He was a wealthy businessman and owned 30 cotton mills in Pennsylvania, a sugar plantation in Louisiana and other investments in railroads and steamships.