Georgia State Route 120

State Route 120
Route information
Maintained by GDOT
Length	75 mi[1] (121 km)
Major junctions
West end	S.R. 100 near Tallapoosa
Major intersections	U.S. 278/S.R. 6 in Dallas S.R. 92 in Hiram S.R. 5/S.R. 120 Alternate in Marietta U.S. 41/S.R. 3 in Marietta S.R. 3 Connector/S.R. 120 Alternate in Marietta U.S. 19/S.R. 400 in Alpharetta I-85/S.R. 403 near Lawrenceville
East end	U.S. 29/S.R. 8 in Lawrenceville
Location
Country	United States
State	Georgia
Highway system
Georgia State Highway System Interstate US State Special
← SR 119 → SR 121

State Route 120 begins at S.R. 100 near Tallapoosa and ends at West Crogan Street (U.S. 29/S.R. 8) in Lawrenceville.

In Marietta, S.R. 120 has a spur route (S.R. 120 Alternate), which acts as a perimeter for the northern part city. From 1969 to 2007, S.R. 120 Loop looped around Marietta. In October 2007, S.R. 120 Loop was decommissioned, and mainline S.R. 120 was rerouted to the southern part of the loop. Prior to October 2007, mainline S.R. 120 ran through downtown Marietta and formed the southern part of Marietta Square. The portion of S.R. 120 from U.S. 41/S.R.3 to S.R. 120 Alternate was renumbered S.R. 3 Connector. This was done at the same time changes were made to S.R. 5.

In Paulding County, the highway cosigns with the following highways (S.R. 360). Then it cosigns with (U.S. 278) through Dallas. In western Paulding County and eastern Haralson County, S.R. 120 cosigns with (S.R. 113). While in northern Fulton County, it cosigns with (S.R. 9) and (S.R. 140) although S.R. 140 just briefly cosigns the highway in Roswell.