Check out Holy Spirit Catholic Church and Christ the King. Both are close to the Buckhead Westin, and Christ the King is super close. I don't know if either of them has rules about needing to be a member to have your wedding there or anything...
Holy Family and St. Ann in Marietta, St. Peter Chanel in Roswell are nice but are 20 to 25 minutes away. Each has a different feel. I can probably play for you if you have it at one of those places. Haha. Traffic is only bad at certain times. But Christ the King is impressive and is definitely a lot closer.
Christ the King is gorgeous and right down the street for the Westin Buckhead! I'm getting married there in May. I am a member already, so not sure about non-members, but just give them a call. They are very knowledgeable. You won't be dissapointed there, it's really beautiful.
I've never been here, but this is another option. It's further away from your reception than Christ the King, but not as far as the ones in Marietta or Roswell that I listed. It's called The Basilica of the Sacred Heart of Jesus. Good luck.
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