Janesville, WI
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The General Motors/Janesville Automotive Transport Company (GM/JATCO) site holds a significant place in Janesville's history. Located at 1000 General Motors Drive and 544 Kellogg Avenue, the property was originally home to the Janesville Assembly Plant, a massive 4.8 million-square-foot facility that operated for nearly 90 years. General Motors ceased operations at the plant in 2008. After years of inaction on redevelopment, the City took ownership of the sites earlier this year to help spur the property's renewal.
To ensure residents have access to the same factual information guiding decision-making, this page offers transparent updates on proposed data center development, brownfield remediation, and the future of the former GM/JATCO site. The City is committed to providing context, clarity, and ongoing communication throughout the redevelopment process.
About the Property
According to the Wisconsin Department of Natural Resources (DNR), a brownfield is a commercial or industrial property, abandoned, idle, or underutilized, where redevelopment, expansion, or reuse is complicated by environmental contamination. Brownfields can range from large former industrial sites to small unused gas stations and typically involve chemical, petroleum, or other hazardous substances that require investigation and cleanup before redevelopment can occur.
The 250-acre former General Motors Janesville Assembly Plant and its surrounding parcels qualify as a brownfield site. The plant ceased operations in 2008, and demolition was completed in 2019. In 2022, the DNR issued a closure letter accepting the remaining concrete foundations and asphalt as a protective cap over the underlying contaminated soil. With this cap in place, the DNR is no longer actively investigating the site, and the property has been granted case closure with continuing obligations.
Case closure does not indicate that contamination has been removed. Contaminants remain in the soil, and the cap is protective only for current conditions. Large areas of cracked pavement, rubble, and overgrown vegetation further complicate redevelopment efforts. Any future redevelopment requires excavation or disturbance of the cap and will trigger additional environmental review and remediation under DNR oversight.
Over the past five years, the site has been submitted to the Wisconsin Economic Development Corporation and Site Selectors for more than ten project leads in sectors such as technology, solar energy, manufacturing, and distribution, representing potential job creation ranging from 130 to 1,700 positions. While the site is attractive due to its size, location, power capacity, and rail access, it has not advanced beyond initial review for any of these opportunities. The primary barriers continue to be the time and financial challenges associated with remediating a large brownfield site.
City of Janesville Enters into LOI with Viridian Partners
At the November 10th City Council Meeting, the City Council voted to enter into a Letter of Intent with Viridian Partners to further explore the potential development of a data center on the property.
What is a Letter of Intent (LOI)?
An LOI is used to confirm serious interest between parties before moving into any binding agreements or detailed due diligence. As a precursor to any contractual obligations, the LOI allows both parties to of information, align project goals, and establish a framework for negotiation.
It is not a contract, but rather an opportunity for the sharing of information and conversations that could lead to framing a contract.
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