I have five direct ancestors that fought in the Union Army during the US Civil War. At least three of them, possibly more, became members of the Grand Army of the Republic (GAR) after the war.
The GAR was a fraternal organization founded in 1866 for honorably discharged veterans of the Union Army, Navy, Marine Corps or Revenue Cutter Service (forerunner of the Coast Guard) who had served between April 12, 1861 and April 9, 1865. The community level organization was called a "Post" and they were numbered consecutively. Many posts were also named after a deceased honoree, typically a local soldier or other military member.
New York State had nearly 700 GAR posts, although not simultaneously. The first, Post 1 Patrick O'Rourke, was organized in 1866 in Rochester NY. Patrick O'Rourke, an Irish immigrant and resident of Rochester, was killed in action on July 2, 1863, on the second day of battle at Gettysburg.
While the GAR posts were originally organized for camaraderie, the group became a political power, counting 409,489 veterans as members by 1890. The GAR founded soldiers' homes, was active in relief work, and in pension legislation. Five US Presidents were members.
My three ancestors that were GAR members are Addison G. Chapman, Delos M. Jones, and Abraham B. Wolff. The evidence I have includes newspaper articles and GAR records.
Addison is included in a photograph of members of GAR Post 166 in Weedsport and a descriptive book (roster) from Post 467 in Westbury.
I have a 1924 newspaper article reporting the election of officers for the Upton GAR post 299 in Batavia, with Delos M. Jones as chaplain.
I have a 1918 newspaper article for Abraham B. Wolff stating that members of E. G. Marshall Post 397 would be attending his funeral.
As the veterans grew older and died, GAR post membership declined. Some posts were consolidated but most disbanded. The last surviving Civil War veteran, Albert Woolson, died in 1956 at age 106. The GAR dissolved after that as Woolson had been the only member.
In New York State, records for the closed and disbanded GAR posts were forwarded to the New York State Archives for storage. Some of the records are digitized and online but not all of them. Last fall, I saw that the New England Genealogical Society was sponsoring a spring 2023 trip to Albany for research at the NYS Archives and library. The tour includes an orientation at the Library and Archives, lectures, consultations with experts, along with logistics like hotel, meals, and a shuttle between the hotel and Library each day. I signed up right away. Albany is a half-day drive for me. I thought this would be a perfect introduction to this important research tool for me, as I have so many ancestors that lived in New York State. One of my main goals for this trip is to see what GAR records are available so I can learn more and find other ancestors that were members.
Hopefully I will find more information - stay tuned!