Microsoft Fairwater Atlanta is an operational AI data center in Fayetteville, GA, USA, with AI chips owned by Microsoft and used by OpenAI (likely) and Microsoft (likely). It hosts an estimated 743k H100-equivalent chips — supported by 636 MW of IT power — at a capital cost of $24.1 B. We estimate that it uses Nvidia B200 chips. The timeline of IT power and compute capacity is based on satellite imagery, our cooling equipment power model, drone imagery, company disclosures, chip availability, and chip efficiency. Built by QTS with Microsoft as the tenant, Fairwater Atlanta likely provides training compute for OpenAI and is disclosed to contain NVIDIA GB200 GPUs.