According to the state's Division of Gaming Enforcement, sportsbooks at the Ocean Resort, Borgata and Monmouth Park reported taking about $3.5m in gross revenue on those bets.
Monmouth Park took about $2.3m in sports bets, Borgata took $986,831 and the Ocean Resort took $192,671.
A total of $15.36m was wagered on events that finished before the end of June, leaving New Jersey sportsbooks with about $1.2m.
Out of the total handle, at least $1m of the wagers were future bets, and these are currently being counted as a win for the bookies, but can change in the future if they have to pay out.
"While it’s still early, we’re obviously off to a great start," William Hill US CEO Joe Asher said. "We always knew there was a big appetite for legal sports betting during the years of litigation, and now it is being proven."
William Hill currently has sportsbooks set up at Monmouth Park and the Ocean Resort.
Sportsbooks paid $300,000 in taxes for the first two weeks of legal sports betting in June.
The total $16.4m wagered on sports in New Jersey is more than double what was reported in the state of Delaware, which reported taking just over $7m in its first 20 days of legal sports betting.
