Janesville Data Center, Janesville, Wisconsin

Janesville's plan for a data center campus on the former General Motors plant site, in Rock County, Wisconsin, is off for now. In June 2026 the city council voted unanimously to let its letter of intent with the developer, Viridian Acquisitions, expire, and the Janesville Gazette reported that the letter dissolved in July without the city or Viridian ever saying publicly whether the project would work at the site.

The city owns the site, the former Janesville Assembly Plant at 1000 General Motors Drive, which General Motors operated from 1919 to 2008. The plant closed in 2009, and the Wisconsin Department of Natural Resources considers the 250-acre brownfield contaminated.

The deal had begun on Monday, November 10, 2025, when the council voted 5 to 2 for a non-binding letter of intent with Viridian Acquisitions LLC, of Colorado, which gave the city 120 days to negotiate. Viridian was weighing an eleven building campus or an eight building hyperscale one, drawing up to 800 megawatts, at a cost of more than $8 billion, with 1,200 construction jobs and 600 permanent posts. Viridian would carry out the cleanup under a plan approved by the Department of Natural Resources.

More than twenty residents spoke against it at the hearing that night. Julie Backenkeller asked the council: "If data centers are so great, then why are so many communities fighting them?" Seth Lambert asked the council to "reject this data center project." Cassandra Pope said: "I don't trust these big, billion dollar corporations, and I don't trust our city government to hold these corporations accountable." Council member Heather Miller voted no: "Without being able to have input from someone about public health makes me concerned for the residents that surround this property."

The opponents then went around the council. No Janesville Data Center gathered 3,927 signatures, twelve more than the 3,915 needed, and they were certified on January 21, 2026. On February 9, 2026 the council put the question on the ballot. On November 3, 2026 Janesville votes on whether any development costing more than $450 million on the undeveloped part of the GM and JATCO site must first be approved by the voters at a general or special election. If the measure passes and a plan is then rejected, the next plan needs another referendum. The question stays on the ballot even though the Viridian plan is gone.

The same week it let the letter lapse, the council voted to develop guardrails on data center development and to study their impact on communities. "It would definitely provide a framework for what the council would deem necessary or acceptable for data centers, should they come to our community," said Nick Faust, assistant to the city manager. In September 2026 Forward Janesville, which had backed the letter of intent, formed Grow Janesville Responsibly to back a proposed data center moratorium and urge a no vote on the referendum, arguing that the city's GM/JATCO advisory board should guide the site plan. The referendum's backers are campaigning for a yes vote, and say they support a data center moratorium too.