AWS confirms 300MW data center campus in Walla Walla

AWS confirmed it is the developer behind a three-building, 300MW data center campus on 134 acres at the Port of Walla Walla, its first in Washington, according to Data Center Dynamics. County documents call the project the Amazon Attalia Data Center Campus.

Each of the three buildings would total 220,000 sq ft, on land between Sundance Road, Dodd Road and Worden Road. The filing also covers a security building, an industrial water facility and a substation pad "to be completed by a future utility provider." The 300MW across 134 acres works out to about 2.2MW per acre.

For allocators underwriting data center development, the unnamed substation utility and approval timing are open due-diligence items. The 300MW figure is preliminary: the substation pad is reserved for a utility not named in the filings, and county approval is still required. Walla Walla County and Facet, a third-party planning consultant, are working through a State Environmental Policy Act review, followed by a second comment period and a formal decision, with no timeline set.

The plan is a scaling back of what was previously intended for the site. Advance Phase LLC bought about 500 acres in the Wallula Gap Business Park for $32.5 million in October 2024, when the site was described as a $4.8 billion, 16-building campus, built in four phases of 125 acres with four 215,000 sq ft buildings each, for more than 3.4 million sq ft in total. The property now being developed is part of 554 acres in the park sold to Amazon Data Services in February 2026.

Just 23 of 706 submissions favored the development, according to Data Center Dynamics. Calls have been made for a full environmental impact statement before the project is fully approved.

AWS has larger greenfield plans elsewhere in the country: up to 15 buildings on 890 acres in Missouri, as Private Wealth Daily previously reported. The next milestone is the county's formal decision, which follows the completed SEPA review and a second comment period.