A view on Wikipedia will show us that many places honored the war dead. I bring up the African American experience because too often, those who are miniorities in our country, have their history forgotten or set aside for other narratives. African Americans also had a hand in this memorial.
From Race and Reunion: The Civil War in American Memory, by Professor David W. Blight:
Our prayer:African Americans founded Decoration Day at the graveyard of 257 Union soldiers labeled "Martyrs of the Race Course," May 1, 1865, Charleston, South Carolina.
The "First Decoration Day," as this event came to be recognized in some circles in the North, involved an estimated ten thousand people, most of them black former slaves. During April, twenty-eight black men from one of the local churches built a suitable enclosure for the burial ground at the Race Course. In some ten days, they constructed a fence ten feet high, enclosing the burial ground, and landscaped the graves into neat rows. The wooden fence was whitewashed and an archway was built over the gate to the enclosure. On the arch, painted in black letters, the workmen inscribed "Martyrs of the Race Course."
At nine o'clock in the morning on May 1, the procession to this special cemetery began as three thousand black schoolchildren (newly enrolled in freedmen's schools) marched around the Race Course, each with an armload of roses and singing "John Brown's Body." The children were followed by three hundred black women representing the Patriotic Association, a group organized to distribute clothing and other goods among the freedpeople. The women carried baskets of flowers, wreaths, and crosses to the burial ground. The Mutual Aid Society, a benevolent association of black men, next marched in cadence around the track and into the cemetery, followed by large crowds of white and black citizens.
All dropped their spring blossoms on the graves in a scene recorded by a newspaper correspondent: "when all had left, the holy mounds — the tops, the sides, and the spaces between them — were one mass of flowers, not a speck of earth could be seen; and as the breeze wafted the sweet perfumes from them, outside and beyond ... there were few eyes among those who knew the meaning of the ceremony that were not dim with tears of joy." While the adults marched around the graves, the children were gathered in a nearby grove, where they sang "America," "We'll Rally Around the Flag," and "The Star-Spangled Banner."
The official dedication ceremony was conducted by the ministers of all the black churches in Charleston. With prayer, the reading of biblical passages, and the singing of spirituals, black Charlestonians gave birth to an American tradition. In so doing, they declared the meaning of the war in the most public way possible — by their labor, their words, their songs, and their solemn parade of roses, lilacs, and marching feet on the old planters' Race Course.
After the dedication, the crowds gathered at the Race Course grandstand to hear some thirty speeches by Union officers, local black ministers, and abolitionist missionaries. Picnics ensued around the grounds, and in the afternoon, a full brigade of Union infantry, including Colored Troops, marched in double column around the martyrs' graves and held a drill on the infield of the Race Course. The war was over, and Memorial Day had been founded by African Americans in a ritual of remembrance and consecration.
ALMIGHTY God, our heavenly Father, in whose hands are the living and the dead; We give you thanks for all your servants who have laid down their lives in the service of our country. Grant to them your mercy and the light of your presence, that the good work which you have begun in them may be perfected; through Jesus Christ your Son our Lord. Amen. (from the BCP)