It varries from state to state, but in 17 of the 50 US States Drafkings Online Sportsbook is 100% legal. Online casino gaming and sports betting is a states rights issue, so in order to use DraftKings Sportsbook/Casino your state would have to have passed legislation allowing it. You do not need to be a resident of the 17 states in order to use it, you just have to be located within the state at the time of your bet. You can check out where DraftKings Sportsbook is available here.