Microsoft founder and philanthropist Bill Gates owns the largest chunk of private farmland in the US across 18 states, a new report has revealed.

Bill and Melinda Gates amassed 242,000 acres of land in the US, with the largest holdings in Louisiana (69,071 acres), Arkansas (47,927 acres) and Nebraska (20,588 acres), according to The Land report.

Bill Gates also owns a stake in more than 24,800 acres of transitional land outside of Phoenix.

Research indicated that the lands across the US is held by Cascade Investment LLC, Gates' private investment vehicle.

"Gates also backs online used-car seller Vroom through Cascade as well as the Canadian National Railway Company," Geek Wire reported.

According to the Tri-City Herald, a 14,500-acre swath of choice Eastern Washington farmland in the Horse Heaven Hills in Benton County has just traded hands for almost $171 million - part of Gates' holdings.

It is unclear why Gates has invested so heavily in farmland, but it could be connected to climate change.

The Bill & Melinda Gates Foundation launched a new nonprofit group a year ago, focused on helping small-scale farmers in developing countries with the tools and innovations they'll need to deal with the effects of climate change.

Bill Gates is currently at the third spot on the Bloomberg Billionaires Index with a net worth of $132 billion.

But even with his big new agricultural holdings, Gates still doesn't rank in the Top 100 private landowners overall in the US, considering owners of land of all types.

The list is topped by Liberty Media's John Malone, with 2.2 million acres of ranches and forests. Amazon CEO Jeff Bezos makes that list at No. 25 with 420,000 acres.