Irvin McDowell
- Dates: October 15, 1818-May 10, 1885
- State: Ohio
- Highest Rank Attained: Major General
- Principal Commands: Army of Northeastern Virginia, I Corps (Army of the Potomac), III (Army of Virginia), Department of the Pacific
- Principal Battles: First Battle of Bull Run (1861), Cedar Mountain (1862), Second Battle of Bull Run (1862)