In 1878, the nation's leading organization of Union veterans of the Civil War, the Grand Army of the Republic, was established for the first time in the Washington Territory. The Department of Washington and Alaska G.A.R. was first created and it's first post, Seattle's Isaac Stevens Post Number 1 was formed. The G.A.R. had been in existence since 1866, but this was the first time it had a formal presence in the Washington Territory.
One year later, in 1879, Seattle had its first Memorial Day observation. In April that year, General Order #5 was issued by Washington G.A.R. leadership, which designated Friday May 30, 1879, as a day "to be observed as Memorial Day in commemoration of the deeds of our fallen comrades." It was requested that all Seattle's "Comrades of the G.A.R., ex-Union soldiers and sailors, and all loyal men and women" join in making the day "a truly fitting tribute to our honored dead, with a hope that this day (late though it may be in the observance of it) may be fully recompense that many years unnoticed if indeed remembered." Memorial Day had been formalized by the G.A.R. in 1868 but it wasn't until a decade later that Washington had its own G.A.R. structure to organize the observation and ceremonies of the day.
A large procession was formed of veterans, groups and citizens of the city that began in front of the Masonic Hall on Front Street and proceeded to the University grounds. There a ceremony was held, orations delivered, poems and prayers read. It was announced that the graves of Union soldiers who were in Seattle's cemeteries had been strewn over with flowers, an important part of the Memorial Day observance. Writing the next day, the Seattle Post-Intelligencer proclaimed "the first observance in Seattle of Memorial Day was a grand affair, and one of which the managers may well be proud. It was much like a celebration of the glorious Fourth of July, leaving out the Declaration of Independence and the use of gunpowder. Our citizens will long remember it and will look for its annual recurrence with unfeigned delight." The annual observation of Memorial Day has endured and continues to this day in Seattle, 143 years later.
The photo below is General Order #5, from the G.A.R. as it appeared in the Seattle Post-Intelligencer, April 1879: