Arizona has the greatest number of species. In terms of literal biomass, Florida likely has the most ants. Nobody knows for certain, though.
Arizona has roughly 330 known ant species, more than any other state. Arizona takes in parts of the Mojave, Sonoran and Chihuahuan Deserts, and its mountains climb from desert scrub up into pine and fir forest. The Chiricahua Mountains alone have more than 180 species recorded, which is more than many entire states. Arizona is also home to some of the most popular desert ants in ant-keeping, including Honeypot Ants like Myrmecocystus mimicus and the Red Harvester Ant, Pogonomyrmex barbatus.
Florida has fewer species, about 230, but when it comes to sheer numbers of ants, it's got the most of any state.
If you're curious what lives near you, our state pages show which of our species are native to your state and which colonies we can ship there.