How do you wager on horse racing online in the U.S.?

Gambling in the U.S., including betting on horse racing, is primarily governed by the states. As of early 2019, 44 states had laws in place authorizing pari-mutuel wagering on horse races.
There’s a lot of variation, though, in how residents of those states can bet. Some states allow betting only at the track. Others have off-track betting facilities at numerous locations. Still others allow wagering on horse racing but have no tracks.
The same goes for wagering by phone or online: Some states allow it; others don’t.
The easiest way to find out if your state offers online betting is to check the handy list we put together. Otherwise, check with one of the major advance deposit wagering (ADW) providers to see if they offer betting in your state.
If none of them do, your only option is to open an account with an offshore betting website that accepts U.S. players. If you decide to do this, I’d recommend doing some research to ensure that the site has been around for a while and has a good reputation of paying on time and fairly resolving disputes.