AWS Marysville data center, Marysville, Ohio

Amazon Web Services is building a $1 billion data center campus, known as Project Cosmo, on 55 acres at 14684 Industrial Parkway in the US 33 Innovation Park in Marysville, Union County, Ohio. Site preparation began in early 2026, with construction to follow through 2027, according to the City of Marysville.

AWS plans two data center buildings totaling about 500,000 square feet. The Marysville City Council approved a reinvestment area agreement on March 10, 2025 that gives AWS a 30-year, 100 percent property tax exemption on the value of the data centers. In return AWS agreed to provide $15 million a year to the Marysville Exempted Village School District and the city over 15 years, according to Data Center Dynamics. The city says the abatement covers only the buildings, not the land, and that the company makes a payment in lieu of taxes each year the abatement runs. "We are proud to reinforce our long-term commitment to the state of Ohio with plans to expand AWS cloud infrastructure in the city of Marysville," said Roger Wehner, AWS's vice president of economic development.

The city's data center FAQ gives no water figure for the campus; it says water use "will depend on the cooling system specified in the plan details" and that on-site wells are not allowed. It says utility upgrades are paid for by the developer and that the facility must comply with local noise ordinances.

A second, larger data center is also approved in Marysville. Following a first reading on November 10, 2025, the City Council approved a reinvestment area agreement with Anadonna, LLC for a data center on about 600 acres known as Marysville South, south of the Union County Airport and west of Industrial Parkway, with 750,000 to 1 million square feet of buildings and more than $1 billion of investment. A Change.org petition started in March 2026 asked the Marysville City Council to reject "the proposed data center," citing water consumption, and closed with 5,757 supporters. AWS is also building elsewhere in central Ohio, with a five-building campus in New Albany and a planned $2 billion campus in Sunbury.

The city expects infrastructure work, including a planned overpass, to run through 2026 and 2027 alongside the AWS construction. Tax and incentive agreements for Marysville data centers go before the Marysville City Council.