Thompson Brothers Rock Art in Giant City State Park preserves four carved names that reflect the Civil War struggle over loyalty and power in southern Illinois. The most prominent inscriptions are Albert S. Thompson, a Union soldier, and T. W. Thompson, a Deputy Provost Marshal who pursued Union deserters; another Union soldier, Thomas L. Bailey, also carved his name, while A. Parker may have been a soldier or a postwar resident. Because the Thompson family were leading local Union supporters, these inscriptions are understood as a deliberate assertion of Northern allegiance in contested ground. The site is now recognized as one of Illinois’s few surviving Civil War sites.