The Grand Army of the Republic, national fraternal organization for Union veterans of the Civil War, was founded in 1866 in Illinois. All soldiers and sailors of the U.S. army, navy, and marine corps who served during the Civil War were eligible for membership, provided that they had an honorable discharge.

Although the Grand Army of the Republic (GAR) became the preeminent veterans' organization arising from the Civil War, its membership grew slowly at first. However, membership rose rapidly during the 1880s and reached its peak in 1890, when 409,489 members were reported. Membership declined thereafter, and the last GAR member died in 1956. For many years, the organization was a powerful political force in its efforts to secure pension increases and other benefits for veterans and their dependents. The GAR also had auxiliary societies such as the Women's Relief Corps, the Ladies of the Grand Army of the Republic, and the Sons of Union Veterans of the Civil War.

Although attempts to organize a GAR department in West Virginia began as early as 1868, it was not until 1880 that Post No. 1 was organized at Martinsburg. A convention to form a permanent state department met in Clarksburg on February 20, 1883, with 11 local posts represented. An annual state encampment was held at different sites in West Virginia. At its peak in 1889, there were 3,161 members in 89 local posts throughout the state.