The Monterey, TN section, about 225 miles north of th Ga. Dome.
If you don't wanna fight the traffic or pay $20 to park next to the dome I suggest using the MARTA. We go down to the Supercross every year and have found it VERY easy to use. WE take 75 south to 285, take 285 West to 20. Once you reach 20 go east (towards Atlanta) and Hamilton Homes should be the first exit. There is a MARTA station there that very easy to find. I think it's $1.75 per person each way and it will take you right up the dome. If you do use it MAKE SURE you get off at the right stop (should be a crowd of orange) ABSOLUTELY MAKE SURE you get back on the rail going west to Hamilton Homes.
If you decided to use the MARTA please rmake sure my directions are correct. The MARTA is easy and safe.