This claim is true. I found some information from the Agricultural Marketing Resource Center. Here is the link: https://www.agmrc.org/commodities-products/fruits/cranberries
It is a reliable site and it gives information about how, "Wisconsin is the leading producers of cranberries, producing 59 percent of the U.S. crop in 2021." This is a little outdated, so I proceeded to find other sources that are more current and came across https://www.wiscran.org/cranberries/. This site, which is also reliable since its focus is Wisconsin Cranberries, mentions that "Wisconsin is the nation’s leading producer of cranberries, harvesting more than 60 percent of the country’s crop." If you scroll down on the page that the link directs you too, it is dated for 2023. To make sure, I did a couple more searches under "Wisconsin Cranberry Production" and numerous articles claiming that Wisconsin is the nation's top cranberry producer come up. They all confirm the same information and claim.