The new wagering business added dozens of jobs at the track for sports betting and additional jobs for security and food and beverage sales.

“It’s put the track on sound fiscal footing,” Mr. Drazen said.

In Atlantic City, the impact of sports betting is mixed. Most casinos have seen revenue decline in the year since sports betting was legalized, but that is largely attributable to two new casinos — the Hard Rock and Ocean Resorts — opening last year and diluting business.

Still, sports betting seems to have helped increase the number of visitors to Atlantic City, officials said.

But by far the most popular form of sports betting in New Jersey is not at the tracks and casinos, but on smartphones: Roughly 80 percent of the bets are made on mobile devices. Bettors have to be physically in the state to make a sports wager.

“Over the past year, New Jersey has in many ways ascended to the center of the sports betting universe thanks largely to the Garden State’s embrace of mobile technology,” said Jamie Shea, the head of digital sports book operations at DraftKings, a sports fantasy company. “We have taken in over 20 million bets via mobile and paid out over $600 million in New Jersey alone.”

The top four mobile betting locations for DraftKings have all been along the Hudson River across from New York City, underscoring the outsize impact of New Yorkers flooding the New Jersey market.