Stone Mountain Depot The former Georgia Railroad depot in Stone Mountain was built in 1856 and enlarged in 1914. It now serves as city hall. Appropriately, it is constructed of stone (granite) from nearby quarries. Stone Mountain is a city of 7,000 on the east side of metro Atlanta.   Georgia's Railroad History & Heritage. Copyright, Steve Storey. Railroad History | The Depot List | Locomotives On Display | Odds & Ends | Sources & References | Home