State Route 138 (SR 138) is a state highway in the northwestern part of the U.S. state of Georgia. The highway is a west-to-east route that travels within portions of Fulton, Fayette, Clayton, Henry, Rockdale, Newton, and Walton counties that connects Fairburn and Monroe. Route description SR 138 begins at an intersection with SR 92 (West Campbellton Street) in Fairburn, within Fulton County. In town, it heads southeast to US 29/SR 14 (Roosevelt Highway). It continues southeasterly to an interchange with Interstate 85 (I-85; James D. "Jim" McGee Memorial Highway) in Union City. Farther to the southeast is SR 279 (Old National Highway), just prior to reaching the tripoint that is the meeting point of Fulton, Fayette, and Clayton counties. It runs along the Fayette–Clayton county line for a short while. During that stretch, it intersects SR 314 (West Fayetteville Road). After entering Clayton County proper, it meets SR 85 in Riverdale. Northwest of Jonesboro is an intersection with SR 138 Spur (North Avenue), which is part of the former route of the SR 138 mainline through town. SR 138 now passes north of most of the town. Just to the northwest of SR 138 Spur is US 19/US 41/SR 3/SR 54 (Tara Boulevard). At this intersection, SR 54 runs concurrent to the east for about . On the northeastern edge of town, SR 54 splits off to the northeast on Jonesboro Road, and SR 138 curves to the southeast to meet is second intersection with SR 138 Spur (Stockbridge Road/Lake Spivey Parkway). Just before crossing into Henry County, SR 138 enters Stockbridge. In town, it has an interchange with I-75. The road re-enters Clayton County and slips out of the city limits for about . It has an interchange with I-675 (Terrell Starr Parkway), during that stretch. After re-entering both Henry County and Stockbridge's city limits, the road meets US 23/SR 42 (North Henry Boulevard). The three routes head concurrent to the east, until just outside the city. After the concurrency ends, SR 138 heads northeast to an intersection with SR 155 (Snapfinger Road), just before entering Rockdale County. The road crosses over the South River and intersects SR 212 (Scott Highway). In Conyers, SR 138 meets SR 20 (McDonough Highway). The two routes run concurrently to the north and northeast through town, with an interchange with I-20/US 278/SR 12 (Purple Heart Highway), until SR 20 heads northwest on