“Memorial Day is a United States federal holiday observed on the last Monday of May (May 31 in 2010). Formerly known as Decoration Day, it commemorates U.S. soldiers who died while in the military service. First enacted to honor Union soldiers of the American Civil War (it is celebrated near the day of reunification after the Civil War), it was expanded after World War I.
By 1865 the practice of decorating soldiers’ graves had become widespread in the North. General John Logan, National Commander of the Grand Army of the Republic–the society of Union Army veterans–called for all GAR posts to celebrate a “Decoration Day” on May 30, 1868. There were events in 183 cemeteries in 27 states in 1868, and 336 in 1869. The northern states quickly adopted the holiday; Michigan made “Decoration Day” an official state holiday in 1871 and by 1890 every northern state followed suit. The ceremonies were sponsored by the Women’s Relief Corps, with 100,000 members.
By 1870, the remains of nearly 300,000 Union dead had been buried in 73 national cemeteries, located mostly in the South, near the battlefields. The most famous are the Gettysburg National Cemetery in Pennsylvania and the Arlington National Cemetery, near Washington.
The Memorial Day speech became an occasion for veterans, politicians and ministers to commemorate the war–and at first to rehearse the atrocities of the enemy. They mixed religion and celebratory nationalism and provided a means for the people to make sense of their history in terms of sacrifice for a better nation, one closer to God. People of all religious beliefs joined together, and the point was often made that the Germans and Irish soldiers had become true Americans in the “baptism of blood” on the battlefield. By the end of the 1870s the rancor was gone and the speeches praised the brave soldiers both Blue and Gray. By the 1950s, the theme was American exceptionalism and duty to uphold freedom in the world.” more here