Alcovy Falls is a scenic 20-foot waterfall found on a tributary of the Alcovy River just east of Lawrenceville. The waterfall lies on private property north of Alcovy Road, right across the river from Freemans Mill Park. Although Alcovy Falls is fairly near the road, it is off limits to the public to the best of my knowledge. The waterfall has become quite the trash dump over the years and I hear it's in need of a serious cleanup. 

To learn about more waterfalls in the Atlanta metro area, see chapter 11 in Mark Ozboyd's "Waterfalls of Georgia" guidebook.