The son of a U.S. Army chaplain, Groves lived at various Army posts during his childhood. In 1918, he graduated fourth in his class at the U.S. Military Academy at West Point and was commissioned into the U.S. Army Corps of Engineers. In 1929, he went to Nicaragua as part of an expedition to conduct a survey for the Inter-Oceanic Nicaragua Canal. Following the 1931 earthquake, Groves took over Managua's water supply system, for which he was awarded the Nicaraguan Presidential Medal of Merit. He attended the Command and General Staff School at Fort Leavenworth, Kansas, in 1935 and 1936; and the Army War College in 1938 and 1939, after which he was posted to the War Department General Staff. Groves developed "a reputation as a doer, a driver, and a stickler for duty" and in 1940 he became special assistant for construction to the Quartermaster General, tasked with inspecting construction sites and checking on their progress. In August 1941, he was appointed to create the gigantic office complex for the War Department's 40,000 staff that would ultimately become the Pentagon.