In the earliest years of the Corps, training was performed by the individual Marine barracks where the individual was recruited before being assigned to a permanent post. Marine non-commissioned officers were responsible for instructing privates in discipline, drill, weapons handling and other skills. Commandant Franklin Wharton established a formal school for recruits at Marine Barracks, Washington, D.C. in approximately 1808, but no records indicate that this served as a centralized recruit depot, and the training regimen remained inconsistent and primitive because of manpower shortages and lack of funding. For example, recruits at Washington were hastily formed into a battalion in July 1861 and drilled as they marched on their way to the First Battle of Bull Run.
In 1911, Commandant William P. Biddle standardized a mandatory two-month recruit training schedule (including drill, physical exercise, personal combat and intensive marksmanship qualification with the M1903 Springfield rifle) and set up four depots at Philadelphia, Norfolk, Puget Sound and Mare Island. In 1915, the Norfolk depot was shifted to its current location at Parris Island, while the Philadelphia and Puget Sound depots were closed and merged with the two remaining depots. As the United States entered World War I, the number of recruits being trained surged from 835 at any given time to a peak of 13,286, while follow-on training was provided at Quantico and in France. During the summer of 1923, the West Coast recruit depot was moved from Mare Island to its current location in San Diego, and the training program was modified to include three weeks of basic indoctrination and three weeks on the rifle range; the final two weeks were occupied in bayonet drill, guard duty, drill and ceremonies.
After Congress authorized an increase in manpower in preparation for World War II in September 1939, the syllabus was halved to four weeks to accommodate the influx of recruits. After standards and marksmanship plummeted as a result, the seven-week schedule was returned and additional training was given at Camp Lejeune or Camp Pendleton, based on specialties, before being assigned to a unit. An additional segregated depot was established at Montford Point for roughly 20,000 African American recruits; integration occurred by 1949. Overall, half a million recruits were trained by the end of the war at the three depots.
During the Korean War, training was shortened from ten weeks to eight but was returned afterward to ten. The Ribbon Creek incident in 1956 led to considerable scrutiny and reform in recruit training, such as an additional layer of command oversight. During the early 1960s, the training period was increased to 13 weeks, including three weeks of marksmanship training at the Rifle Range. The Vietnam War-era syllabus was shortened to eight weeks and again saw infantry recruits attend follow-on training at Lejeune and Pendleton.