American voters used Tuesday's midterm ballots to push back against data centre building, rejecting or limiting projects in nearly every local contest that put the issue to a vote.

An election monitoring project tracked 41 ballot measures tied to data centres across the country. Voters were on course to reject data centre development in all but one of those fights, with two races still being counted but expected to favour limits. The sole clear exception was Harwood, North Dakota, a town of fewer than 800 people, where voters defeated a measure that would have required independent reviews of large industrial projects such as data centres before construction.

The results follow months of local anger over power use, water demand, noise and land consumption linked to the computing halls that train and run artificial intelligence systems. A September poll had found that about 70 percent of respondents opposed new data centres near their communities. Democrats sought to channel that backlash during the campaign, and Tuesday's local tallies suggest the opposition translated into votes even where national party contests dominated headlines.

For the technology industry the message is practical. Expansion plans that assume easy local approval now face a map of hostile ballot outcomes, slower permitting and higher political risk just as investors debate how midterm Democratic gains will shape federal rules on artificial intelligence infrastructure. For residents the votes were often framed more simply as a stand over electricity bills, water and who decides what gets built next door.