Gouverneur Kemble Warren (January 8, 1830 – August 8, 1882) was an American civil engineer and Union Army general during the American Civil War. He is best remembered for arranging the last-minute defense of Little Round Top during the Battle of Gettysburg and is often referred to as the "Hero of Little Round Top". His subsequent service as a corps commander and his remaining military career were ruined during the Battle of Five Forks, when he was relieved of command of the V Corps by Philip Sheridan, who claimed that Warren had moved too slowly. Early life Warren was born in Cold Spring, Putnam County, New York, and named for Gouverneur Kemble, a prominent local Congressman, diplomat, industrialist, and owner of the West Point Foundry. His sister, Emily Warren Roebling, would later play a significant role in the building of the Brooklyn Bridge. He entered the United States Military Academy across the Hudson River from his hometown at age 16 and graduated second in his class of 44 cadets in 1850. He was commissioned a brevet second lieutenant in the Corps of Topographical Engineers. In the antebellum years he worked on the Mississippi River, on transcontinental railroad surveys, and mapped the trans-Mississippi West. He served as the engineer on William S. Harney's Battle of Ash Hollow in the Nebraska Territory in 1855, where he saw his first combat. He took part in studies of possible transcontinental railroad routes, creating the first comprehensive map of the United States west of the Mississippi in 1857. This required extensive explorations of the vast Nebraska Territory, including Nebraska, North Dakota, South Dakota, part of Montana, and part of Wyoming. One region he surveyed was the Minnesota River Valley, a valley much larger than what would be expected from the low-flow Minnesota River. In some places the valley is 5 miles (8 km) wide and 250 feet (80 m) deep. Warren first explained the hydrology of the region in 1868, attributing the gorge to a massive river, which drained Lake Agassiz between 11,700 and 9,400 years ago. The great river was named Glacial River Warren in his honor after his death. Civil War At the start of the war, Warren was a first lieutenant and mathematics instructor at the United States Military Academy at West Point. He helped raise a local regiment for service in the Union Army and was appointed lieutenant colonel of the