A unique, twin waterfall with a rich history, Costley Mill Falls lies along Big Haynes Creek just northeast of Conyers. About 12 feet high, this waterfall lies in the Costley Mill Park along Old Costley Mill Road, operated by Rockdale County. It is one of the park's main focal points and can be seen from the grounds without any hiking. 

The right side of the falls is a long slide dropping into a spectacular pool with a nice beach. This hidden gem swimming hole is one of Metro Atlanta's best spots to beat the summer heat. Meanwhile, the left side of the falls has a more vertical appearance and is tied to an old sluiceway from the historic Costley Mill. 

This waterfall was once home to a lively settlement, which included a gristmill, sawmill, planning mill, and cotton gin. The mill survived the Civil War and operated until it burned down in 1973. Numerous stone structures and other mill ruins can be seen on the rocks around Costley Mill Falls today. 

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