Dayton R. Leland was born around 1822 in New York to James and Diana Leland. His father was a farmer who owned $400 of real estate in 1850. Leland attended the preparatory department at Oberlin College in 1842 before enrolling at Albany State Normal College in the late 1840s. He married Julia Ann Hill in the 1850s, and they had at least two children: Hettie, born around 1858; and Hannibal, born around 1859. By 1860, they were living in Newfane, New York, and Leland was working as a teacher. They owned $800 of real estate and $350 of personal property.
He enlisted in the Union army on August 21, 1862, and mustered in as a private in Company G of the 49th New York Infantry on September 10. According to his service records, he was 5 feet, 9 inches tall, with dark hair and blue eyes. The regiment took part in the siege of Yorktown, the Battle of Williamsburg, the Seven Days’ Battles, the Battle of Antietam, the Battle of Fredericksburg, the Battle of Chancellorsville, the Battle of Gettysburg, and the Overland Campaign. He was severely wounded in the leg on May 12, 1864, in the Battle of Spotsylvania Court House. Union officials brought him to a hospital in Fredericksburg, Virginia, and he probably died there soon afterward.