Figures released Wednesday by the state Division of Gaming Enforcement show the casinos won $221.8 million in March. That's an increase of 9.3 percent compared with March 2016.
The results were helped by an increase of 40.2 percent in online gambling revenue, which increased to $21.7 million in March, compared with $15.5 million a year ago.
Of the seven brick-and-mortar casinos currently operating, only Bally's posted a decrease, and it was only 2.2 percent.
Internet gambling began in New Jersey in November 2013 as a way to help the state's struggling casinos. It appears to be doing just that, gambling authorities said.
"Every month should be as good as March was," said Matt Levinson, chairman of the New Jersey Casino Control Commission. "When coupled with the very strong earnings report that came out last week, it's clear that casinos have started to grow the market and increase their profits. That is generating a lot of positive interest in Atlantic City and has already attracted significant new investment in this market."
In recent months, Hard Rock International bought the former Trump Taj Mahal casino, which was shuttered in October, and announced plans to reopen it in summer 2018. And some local developers have bought the former Atlantic Club casino and plan to reopen it as a non-gambling water park resort.
David Rebuck, director of the gaming enforcement division, called the March numbers "further proof of the industry's stability during the past 18 months."
"For the first three months of 2017, internet gaming revenue is up 32 percent compared to last year, and the (online) industry is on pace for another record year," he said.
The Tropicana saw the largest monthly increase, up 37.6 percent to $35.2 million. Casino president Tony Rodio said the Tropicana continues to benefit from ongoing capital improvements to the property, such as new Jose Garces restaurants, a recently renovated Havana Tower and renovations to the casino floor.
"Overall, I think March is a great indicator of the overall health of the Atlantic City market," Rodio said.
The five casinos that offer internet gambling took in between $3.1 million (Caesars Interactive-NJ) and $6.1 million (Golden Nugget). Resorts Digital saw its online winnings increase by more than 123 percent in March, from $1.8 million in March 2016 to $4.2 million last month.
New Jersey is one of only three states that offer internet gambling, along with Nevada and Delaware. Other states are considering legalizing it.