Lithonia (/lɪˈθoʊniə/ lih-THOH-nee-ə, AAVE: /laɪ-/ ly-) is a city in eastern DeKalb County, Georgia, United States.

[4] The huge nearby Stone Mountain is composed of granite, while the Lithonia gneiss is a form of metamorphic rock.

Lithonia is one of the gateways to the Arabia Mountain National Heritage Area,[5] which is largely contained inside Stonecrest, Georgia.

The town grew with the coming of the Atlanta Augusta Railroad in 1845, which allowed the granite quarrying industry in the area to flourish.

The Lithonia Historic District consists of a commercial core surrounded by residential areas, with a period of significance spanning from 1845 to 1964.

The district is bisected by the Georgia/CSX Railroad, which runs perpendicular to the historic commercial core's primary thoroughfare, Main Street.

Contributing sites in the district include two cemeteries, two parks, the former Georgia Railroad Quarry, and the ruins of the Bruce Street School for African-Americans (1938).

Redan post office located directly outside the city limits of Lithonia provides an alternative to postal drop off and pickup service.

MARTA (Metropolitan Atlanta Rapid Transit Authority) provides connecting bus service to and from Lithonia, and GRTA Xpress (Georgia Rapid Transit Authority) provides commuter bus service to downtown Atlanta from a community park and ride lot.