Amazon opens $11bn AI data centre 'Project Rainier' in rural Indiana

Amazon opened Project Rainier, an $11bn AI data-centre campus outside Indianapolis, Indiana, built primarily to run training and inference workloads for Anthropic. Seven buildings on the site currently house close to 500,000 of Amazon’s custom Trainium2 chips, with Amazon saying the count would exceed a million by the end of 2025; longer-term plans call for 23 further buildings and more than 2.2 gigawatts of capacity. The site sits on roughly 1,200 acres of land Amazon has been assembling in rural Indiana since 2023.

The chips are organised into servers of 16 Trainium2 processors each, four of which are linked by Amazon’s NeuronLink interconnect into a 64-chip “UltraServer”, and Amazon said the buildout represents its largest known deployment of AI compute that isn’t built on Nvidia hardware. Amazon has invested roughly $8bn in Anthropic since early 2024, and the two companies said Anthropic’s engineers had contributed technical input to the site’s chip and infrastructure design. A next-generation chip, Trainium3, developed with Anthropic’s input, is expected to ship before the end of the year, which Amazon said would roughly quadruple per-chip performance.

Project Rainier’s opening put a concrete facility behind Amazon and Anthropic’s long-running characterisation of their partnership as an alternative to the Nvidia-dependent, Microsoft- and Oracle-backed infrastructure that OpenAI has built through Stargate — a project OpenAI has separately said it wants to scale to 33 gigawatts. The comparison illustrated a divide opening up in frontier AI infrastructure between labs training primarily on merchant Nvidia GPUs and those, like Anthropic and Google, training substantially on custom silicon supplied by their cloud-provider backers. As with other announcements of this kind, the reported cost and chip figures came from Amazon and were not independently audited.