The Georgia Marathon takes place every year in March, with the marathon and the half-marathon starting and ending at Centennial Olympic Park in downtown Atlanta (see area map).  The race course goes through intown neighborhoods, including Inman Park, Virginia Highland, Decatur, Midtown and Druid Hills.

From the North or South (red/gold rail lines)
Take a red or gold line train to the Peachtree Center station.  Take the Harris Street exit off the train platform then follow the signs pointing to Peachtree Street West after going through the fare gate.  At street level, turn right on Peachtree Street then right at the first light on to Andrew Young International.  This street will go right to the park.

From the East or West (blue/green rail lines)
Take a blue or green train to the Dome/GWCC/Philips Arena station, which is one stop away from Five Points.  Follow the signs pointing to Philips Arena after exiting the station.  After going up an escalator and flight of stairs, walk straight ahead past Philips Arena (the arena will be on your left).  The park is about two blocks down.

For more information, see see: 
MARTA Maps
Google Transit App
Navigating the Peachtree Center Station
Best of the Dome Station
Top 5 MARTA Stations to Park and Ride