Voters in Janesville, Wisconsin, will decide on a ballot initiative on Nov. 3, 2026, that would require voter approval before a proposed $8 billion data center can be developed.

On Feb. 9, 2026, the Janesville City Council voted to include the ballot initiative on the general election ballot. No Janesville Data Center organized the petition drive. Petitioners were required to collect signatures equal to 15% of the 26,082 votes cast in Janesville in the most recent gubernatorial election, resulting in a requirement of 3,915 signatures. On Jan. 21, the clerk's office certified 3,927 signatures.

The ballot initiative would require voter approval before the City of Janesville could approve development on undeveloped portions of the GM/JATCO site if the project’s cost exceeds $450 million. Approval would require a majority vote at a general or special election. If voters reject the proposal, any new development plan or agreement for the site would require a new referendum.

The GM/JATCO site is city-owned property, formerly known as the Janesville Assembly Plant, located at 1000 General Motors Drive and 544 Kellogg Avenue. General Motors operated the Janesville Assembly Plant from 1919 to 2008.

As of February 2026, the Janesville City Council was considering a proposal from Viridian Partners to redevelop the site into an 800-megawatt, 11-building data center campus. The project was estimated to cost $8 billion.

Supporters of the initiative organized under the name No Janesville Data Center. Should the initiative be enacted, a project of that cost ($8 billion) would require voter approval. Any future project over $450 million would require voter approval.

Voters in other cities may also decide on ballot measures related to data centers in 2026. An initiative, similar to the one in Janesville, was certified for the ballot in Port Washington, Wisconsin. On Feb. 10, signatures were submitted for a referendum in Marana, Arizona. Petitions are also circulating in Frederick County, Maryland, and Joplin, Missouri.