James Nagle (April 5, 1822 – August 22, 1866) was an officer in the United States Army in both the Mexican–American War and the American Civil War. During the latter conflict, he recruited and commanded four infantry regiments from the commonwealth of Pennsylvania and led two different brigades in the Eastern Theater. As the war progressed, worsening health problems precluded prolonged field service, but Nagle is perhaps best known for his actions at the 1862 Battle of Antietam, where his brigade played a key role in securing Burnside's Bridge, a key crossing over the contested Antietam Creek.