WASHINGTON --- Many installations across the Army this year are marking the centennial of the construction of their posts, which occurred in the weeks and months following the U.S. declaration of war on Germany, April 6, 1917.Prior to World War I, the Regular Army numbered just 133,000 Soldiers. At the time, an additional 400,000 served in the Army National Guard. By the end of World War I, the combined total of active and National Guard had grown to over four million, said Eric Setzekorn, a historian at the Center of Military History."Never before or since has the Army experienced a comparable period of massive expansion, coupled with unprecedented organizational transformation, in such a brief period as during 1917 to 1918," he said.To house and train all of the new Soldiers, hastily constructed camps sprouted up across the country, 16 of which were Guard installations, he said. Swamps were drained and forests were cleared to build parade fields and roads, and to erect barracks and chow halls. Small cities of 30,000 to 40,000 Soldiers seemed to materialize overnight.Many of the installations took on names of Civil War generals such as Camp Meade, Camp Gordon, Camp Lee and Camp Jackson, he said. Fort Belvoir was originally called Camp Humphreys, also the name a Civil War general. The name changed after the war.The Civil War wasn't the only source of names for new camps. Camp Travis, for instance, was named for a hero of the Battle of the Alamo. It later became Fort Sam Houston and is now Joint Base San Antonio. Camp Dix was named for a veteran of the War of 1812 and the Civil War. After the war it was re-named Fort Dix and today is part of Joint Base McGuire-Dix-Lakehurst, in New Jersey.Camp Funston, named for Spanish-American War leader Maj. Gen. Frederick Funston, eventually became Fort Riley. Camp Lewis, in Washington state, was named for early American explorer Meriwether Lewis. That installation became Fort Lewis, and is now known as Joint Base Lewis-McChord.A few camps, like Camp Cody near Deming, N.M., and Camp Wadsworth, near Spartanburg, S.C., were inactivated following the end of the war.COMMUNITY EFFORTCommunity involvement in setting up the camps was essential, Setzekorn said. Not only did people from the surrounding communities help build the new camps and then work there, they were also instrumental in getting the camps there in the first place.Take Fort Jackson, S.C. When word came down that a location was needed to house and train Soldiers, the people in the nearby city of Columbia saw the new Army post as being potentially good for business, public relations and patriotism, Setzekorn said. "So they acquired the land, cleared the trees, drained the swamps and basically started building from scratch."Other camps across America had similar stories of communities eager to pitch in and do their part for the war effort, he said.IN THE ARMY NOWMany of the arriving recruits had never ventured far from home, Setzekorn said. The vast majority had also never experienced military life. Army chow replaced their mom's cooking. Recruits learned close-order drill, marksmanship and how to use their bayonets. And every Soldier was issued brown doughboy uniforms.It was a culture shock for some, he said. And it was a double challenge for the many recruits who had recently immigrated to the U.S. and hadn't yet learned English.Once their training at the camps was complete, the Soldiers were ready to ship out to France.Soldiers boarded troop trains for the journey to the East Coast where they would await transport across the Atlantic. The largest embarkation facility was Camp Merritt near Tenafly, N.J., about 10 miles from New York City. The location had good access to rail, he said, noting that the Interstate Highway System was decades away from being built and that rail was the preferred mode of travel.In the two-year period from the summer of 1917 through 1919, roughly 1.6 million Soldiers passed through the ports that surrounded New York City. More than one million of those Soldiers passed through Camp Merritt. That installation was later closed, Setzekorn said, never to reopen.Newport News, Va., functioned as the secondary embarkation port for Soldiers. Nearly 300,000 were processed over the course of the war from that location. Another 140,000 Soldiers departed from ports ranging from Baltimore, Md. to Qu├ębec, Canada.For the tens of thousands of Soldiers who died in combat while in Europe, these embarkation ports would be the last American soil they would ever see.DEMOBILIZATIONAfter the war, which ended Nov. 11, 1918, the new camps became demobilization centers for the returning doughboys.Setzekorn said the establishment of the camps, along with advancements in military tactics, technology and organizational structure, "laid the foundation for not only the American Expeditionary Force's contribution to Germany's eventual defeat, but also to the creation of the modern U.S. Army and the emergence of America as a world power."