San Antonio, Texas, has been called Military City USA for many years. It earned this sobriquet not only by virtue of its major military installations but also because of its close and cordial relationship with the US Armed Forces. But in 1916, the year before America entered the Great War, all of that was still in the future. Fort Sam Houston was the largest US Army post in the country, but its attention was focused on the border with Mexico. This changed on April 6, 1917, as the United States needed to quickly raise an expeditionary army of three million men with its attendant air service and send it overseas. This volume portrays the growth of military facilities and infrastructure in San Antonio during World War I that started the Alamo City on the road to becoming Military City USA.