Nate,

You need to get your dictionary out. In earlier times, a casino was place for "public entertainment". Dancing was common, but there were other forms of entertainment as well. If you search the postcard section of eBay for "casino" you will find many old style, turn of the century, casinos from places in the Northeast, including Atlantic City. They could also be found in Miami, Chicago and California. Common theme is that most were by the water.