One of the World’s Largest Geothermal Networks Is Buried Beneath a Corporate Campus in Rural Wisconsin

Tech company Epic Systems uses over 6,000 boreholes to help heat and cool its office buildings, making its Verona, Wisconsin campus one of the largest geothermal networks in the world.

Epic, which houses the medical records for 325 million patients, has been drilling additional boreholes at its headquarters since it completed its first borefield in 2006. In late 2025, Epic began a project to expand its network by adding 2,400 more boreholes.

Epic's buildings use approximately one-quarter the amount of energy as typical office buildings, with more than half the energy reduction coming from the geothermal system.