There are 39 states with some form of legalized gambling, according to the American Gaming Association. Of those states, 28 have Indian casinos, 23 have commercial casinos, and 14 have racetrack casinos. In 2012, commercial casinos brought in $37.34 billion across the country, but in seven states — Delaware, Indiana, Michigan, Missouri, New Jersey, New Mexico, and West Virginia, revenue decreased from 2011 to 2012.
For more information, see Flowing Data’s interactive map here.