James J. Byrne, United States army officer, was born in Ireland and moved to New York at an early age. On July 24, 1862, he was commissioned a first lieutenant and appointed adjutant of the 163d New York Infantry. He left the regiment on December 11, 1862, but on February 24, 1864, was appointed colonel of the Eighteenth New York Cavalry. As a member of Maj. Gen. Nathaniel P. Banks's Army of the Gulf, he saw extensive action in Louisiana during the Red River campaign of 1864. Byrne was brevetted to brigadier general for gallantry at the battles of Pleasant Hill and Campti and to major general for his conduct at the battles of Moore's Plantation (May 5–6, 1864) and Yellow Bayou (May 18, 1864), both brevets being issued on March 13, 1865. According to a report in the Fort Worth Democrat (see FORT WORTH STAR-TELEGRAM), he was the youngest general in the United States Army. He was mustered out of volunteer service on May 13, 1866.
President Andrew Johnson then appointed him United States marshal for the Northern District of Texas, with headquarters in Fort Worth. Byrne was mentioned as a possible conservative candidate for Congress from the Galveston district and was commended by the Dallas Herald for his defense of James W. Throckmorton in connection with a financial scandal. Although Byrne was popular with the citizens of the district, President Ulysses S. Grant replaced him in office, and the former marshal turned to surveying in the Fort Worth area and was retained as chief engineer of the Texas and Pacific Railway. Early in July 1880 he left Fort Worth for El Paso with a party of fifteen men, guided by the notorious Pat Doolan, to survey railroad lands in the Guadalupe Mountains. On August 2 he was at Ysleta, where he learned that Apache chief Victorio had once again crossed into the Big Bend region from Mexico and was attacking such targets of opportunity as presented themselves. Perhaps with a sense of foreboding, he penned a letter to his wife, Lilly (Loving), and his last will and testament–"my last goodbye to all I love upon this earth"–at the Texas and Pacific station and, bound by "either honor or self respect," pushed on toward the Guadalupe Mountains. On August 10 Byrne left Fort Quitman for the Pecos on a stagecoach driven by seventeen-year-old Charles D. West. The coach was attacked by Victorio's band about nine miles east of Fort Quitman, and although West managed to turn it around and start for the shelter of the fort, two of the Indians overtook the coach and fired into it, wounding Byrne first in the hip and then in the small of the back. According to newspaper report, Byrne was unarmed, and West's Winchester rifle had only two cartridges. No doctor was nearer than El Paso. Byrne died of gangrene on August 14, 1880. "I never saw a man die braver," said West.
Byrne's estate amounted to an estimated $25,000. His one child died as an infant, and Byrne requested that his own remains, "if they be found," be buried by its side. He was first buried at Fort Quitman but was later removed to Fort Worth, where he was reinterred on November 21. According to the Fort Worth Democrat Byrne was "a man of indomitable energy and courage, always ready to discharge any duty fully and freely which came upon him." His final advice to his wife was that she leave Texas "and seek some other home" where she might "find the peace and rest denied you here." A historical marker in Hudspeth County marks the site of Victorio's attack.