Amazon Web Services (AWS), now confirmed as being the developer behind the data center campus in the Port of Walla Walla, Washington, has revealed details about the project.

Documents shared by Walla Walla County state that the Amazon Attalia Data Center Campus will include three 220,000 sq ft (20,440 sqm) data center buildings on 134 acres of land between Sundance Road, Dodd Road, and Worden Road.

The campus is expected to have a 300MW power capacity.

AWS will also develop a security building on site, an industrial water facility, and a pad for a substation "to be completed by a future utility provider."

The property being developed is part of the 554 acres of land in the Wallula Gap Business Park sold to Amazon Data Services in February 2026.

A public comment period ended in mid-October, in which just 23 of 706 submissions were in favor of the data center development. Those in favor recommended controls be in place, including that "the ecology of the Walla Walla Valley must be protected."

Calls have been made for a full Environmental Impact Statement to be provided before the project is fully approved.

AWS' plans for the campus are a significant scaling back of what was previously intended for the site. A State Environmental Policy Act review is being worked on by Walla Walla County and Facet, a third-party planning consultant.

Once completed, AWS will be able to review issues raised, and a second public comment period will be entered. Only then will the county make a formal decision regarding the development, with no set timeline yet provided.

In October 2024, Advance Phase LLC purchased some 500 acres in the Wallula Gap Business Park for $32.5 million for a data center campus. At the time, the end user company behind the project was unknown.

At the time of purchase, it was said that the site was planned to be home to a $4.8bn data center campus, totaling 16 buildings.

The company intends to build data centers in four phases of 125 acres each; each phase would feature four 215,000 sq ft (19,975 sqm) buildings, for a total of more than 3.4 million sq ft (315,870 sqm).

The Wallula Gap Business Park is a 1,900-acre heavy industrial site adjacent to US Highway 12, Union Pacific Railroad mainline, and ten miles (16km) from Interstate 395. Walla Walla is located in the southeast of Washington state, around a four-hour drive from Portland, Oregon. AWS has an existing cloud region in Oregon.

The state has a notable data center presence, with most facilities located around Seattle and a secondary market in Quincy.