The Grand Army of the Republic [the GAR] was founded April 6th 1866 in Decatur, Illinois.
When the Civil War came to an end the veterans wishing to stay in contact created many organizations. These groups were created at first for sake of camaraderie and their shared experiences, but later became a political power. The eventual leaders of the organizations was the GAR which was founded by Benjamin F Stephenson in Decatur, Illinois on April 6th 1866.
The GAR, which welcomed both black and white Union veterans, quickly became an arm of the Republican Party. They worked towards voting righted for all black Union veterans. In the 1880’s the GAR began to work on federal pensions and with the founding of old soldiers’ homes.
The members of the GAR wore military style uniforms at meetings. The organization could be found in every one of the State as well as several foreign countries. At the state level the GAR groups were known as “Departments”, at the local level they were called “Posts”. “Posts” were numbered consecutively as they formed, with the rule that each of the “Posts” be named for an honored deceased person. The GAR even had one woman who was a member, Sarah Emma Edmonds, who had fought in the Civil War as part of the 2nd Michigan Infantry under the name of Franklin Thompson. In the 1890’s the GAR had about 490,000 members, all honorably discharged Union veterans. They held National Encampments, annually from 1866 to 1949. These Encampments were multiday events with formal dinners and memorial services. The last Commander of the GAR was Theodore Penland of Oregon, and last member was Albert Woolson of Duluth, Minnesota who was 109 years old when he died in 1856.
If you’re interested in reading more, check out the web site A Brief History of the Grand Army of the Republic