Edmund Kirby Smith (May 16, 1824 – March 28, 1893) was a Confederate States Army general, who oversaw the Trans-Mississippi Department (comprising Arkansas, Missouri, Texas, western Louisiana, Arizona Territory and the Indian Territory) from 1863 to 1865. Before the American Civil War, Smith served as an officer of the United States Army.

Smith was wounded at the First Battle of Bull Run and distinguished himself during the Heartland Offensive, the Confederacy's unsuccessful attempt to capture Kentucky in 1862. He was appointed as commander of the Trans-Mississippi Department in January 1863. The area included most actions east of the Rocky Mountains and west of the Mississippi River. In 1863, Smith dispatched troops in an unsuccessful attempt to relieve the Siege of Vicksburg. After the United States took control of Vicksburg in July, the Trans-Mississippi Department was cut off from the rest of the Confederacy and became virtually an independent nation, nicknamed "Kirby Smithdom".

In the Red River Campaign of Spring 1864, he commanded victorious Confederate troops under Major-General Richard Taylor, who defeated a combined Union Army and Navy assault under U.S. Major-General Nathaniel P. Banks. On June 2, 1865, Smith surrendered his army at Galveston, Texas, the last general with a major field force.

He quickly fled to Mexico and then to Cuba to avoid arrest for treason. His wife negotiated his return during the period when the U.S. government offered amnesty to those who would take an oath of loyalty to the United States. After the war, Smith worked in the telegraph and railway industries. He also served as a professor of mathematics at the University of the South in Tennessee. He botanized plant specimens and bequeathed his collection to the University of Florida.

Edmund Kirby Smith was born in 1824 in St. Augustine, Florida, as the youngest child of Joseph Lee Smith, an attorney, and Frances (née Kirby) Smith. Both his parents were natives of Litchfield, Connecticut, where their older children were born. The family moved to Florida in 1821, as the senior Smith was appointed as a Superior Court judge in the new Florida Territory, acquired by the U.S. from Spain. Older siblings included Ephraim, born in 1807; and sisters Frances, born in 1809, and Josephine, who died in 1835, likely of tuberculosis. He was interested in botany and nature, but in 1836, Smith's parents sent their second son to a military boarding school in Virginia, and strongly encouraged a military career. He later enrolled in the United States Military Academy.

In 1837, his sister Frances married Lucien Bonaparte Webster, a West Point graduate from Vermont and career U.S. Army artillery officer, whom she met when he was stationed at Fort Marion in St. Augustine. His commanding officer at the fort was the young Smiths' uncle. Webster later served in the Mexican–American War and died of yellow fever in 1853 when stationed on the Texas frontier at Fort Brown.

On July 1, 1841, Smith entered West Point and was graduated four years later in 1845, ranking 25th out of 41 cadets. While there, he was nicknamed "Seminole", after the Seminole people of Florida who had successfully resisted removal by the United States. He was commissioned as a brevet second lieutenant in the 5th U.S. Infantry on July 1, 1845. Smith was promoted to second lieutenant on August 22, 1846, now serving in the 7th U.S. Infantry.

In the Mexican–American War, Smith served under General Zachary Taylor at the Battle of Palo Alto and the Battle of Resaca de la Palma. He later served under General Winfield Scott and received brevet promotions to first lieutenant for Cerro Gordo and to captain for Contreras and Churubusco. His older brother, Ephraim Kirby Smith (1807–1847), who was graduated from West Point in 1826 and was a captain in the regular army, served with him in the 5th U.S. Infantry in the campaigns with both Taylor and Scott. Ephraim died in 1847 from wounds suffered at the Battle of Molino del Rey.