The link above is the number 1 source for finding anime cons worldwide at the moment. From small cons to large you should be able to find it. Unfortunately you can only narrow the location down to North america, then scroll from there while skimming and jotting down all cons in your state or how ever far you’re willing to drive. but its worth the work.
In case you haven’t been to a Con before, here is a video of some cosplays from the (currently) largest con in the United States. Anime Expo in LA California