By 1850, Mercersburg had 26 freedman households, and many former slaves worked in skilled trades as carpenters, carriage builders, blacksmiths, and quarrymen. A smaller squatter community west of town was known as Africa, and with an active Underground Railroad throughout the area, Africa, a few miles north of the Mason-Dixon Line, was a haven for freedmen and escaped slaves. In 1863, when African Americans were given the opportunity to join the Union Army, many men from both communities answered the call. Eighty-eight African Americans from Mercersburg volunteered to defend the Union during the Civil War, with forty-four enlisting in either the 54th or 55th Massachusetts Infantry and forty-four others joining various United States Colored Troops units. At least 36 of those veterans lie in Mercersburg Zion Union Cemetery, established in 1876 by local Black citizens. Veterans known to be buried there served in the Pennsylvania United States Colored Troops 8th, 22nd, 24th, 25th, 32nd, 41st, and 127th regiments, as well as the 54th Massachusetts, 55th Massachusetts, and the 2nd U.S. Colored Cavalry. The twelve soldiers from the 54th Massachusetts interred there constitute one of the largest known groups from that unit buried in a private cemetery.
