Iowa has ranked as one of the least sinful states in the U.S. But Iowa is continuing to go up on this list. So, is Iowa actually getting more sinful as time goes on?. Luckily, Iowa continues to be in the top 10 least sinful states making it one of top nicest states or one of the least naughtiest state. Iowa actually got a little naughtier for 2024 and one of its neighboring states is going down the list.