There are quite a lot of online operators in Pennsylvania, each of which operates in partnership with a land-based PA casino that has been approved for a license. You can be a visitor just have to be physically located within state lines. Remember, you don't have to live in Pennsylvania to play.
In fact, PA has one of the biggest selections of land-based and online casinos in the whole country, so if you're looking for variety it's a great place to start. Despite a slow start to legalized online gambling in Pennsylvania, a huge library of games is now available on the state’s legal casino sites. Pennsylvania online casino games became legal in 2017 and the first games to finally go live rolled out in July 2019.