Mount Jackson is a town in Shenandoah County, Virginia, United States. The population was 1,994 at the 2010 census. For highway travelers passing by, Mount Jackson is easily identified from I-81 exit 273 by the water tower painted as a basket of apples, which was recently repainted. For those exploring off the highway, the town has history as a comm…Mount Jackson is a town in Shenandoah County, Virginia, United States. The population was 1,994 at the 2010 census. For highway travelers passing by, Mount Jackson is easily identified from I-81 exit 273 by the water tower painted as a basket of apples, which was recently repainted. For those exploring off the highway, the town has history as a commercial and railroad hub in the region, with rich Civil War heritage and a historic district listed on the National Register of Historic Places.