McAllister's Mill Underground Railroad Station. At their grist mill on nearby Rock Creek, James McAllister and his family provided temporary shelter to hundreds of fugitive slaves. Now in ruin, it was part of one of the earliest UGRR networks through which freedom seekers passed on their way north. It was the site of a significant gathering of abolitionists on July 4, 1836, that led to the formation of the Adams County Anti-Slavery Society, an early and influential abolitionist organization.