Maryland Live ! casino prior to opening to the public on June 6. (Mark Gail — The Washington Post)

The June haul at the casino at Arundel Mills mall was twice that of Maryland’s two previously opened gaming venues combined. Nearly half of Maryland’s slots revenue is earmarked for education programs.

Maryland Lottery Director Stephen Martino characterized the numbers from Maryland Live!, which opened to overflow crowds and traffic congestion on June 6, as “extremely strong.”

“You could tell there was palpable excitement at the facility if you were there on opening night,” said Martino, whose agency regulates Maryland’s slots program, which voters approved in 2008.

Officials from the Cordish Cos., which owns and operates the Anne Arundel County venue, said that more than 500,000 people visited Maryland Live! during its first 24 days of operation.

“The results are right in line with projections,” said Joe Weinberg, managing partner with Cordish.

The venue — which also features a half-dozen new restaurants — opened with nearly 3,200 slot machines. That figure is expected to grow to 4,750 by fall, making Maryland Live! one of the largest casinos in the country by that measure.

It is not likely to become the most lucrative, however. Last month, Resorts World, a new slots casino at Aqueduct racetrack in New York City, reported $57.5 million in gross gaming revenue in May, tops in the country.

The boost to the bottom line for Maryland’s slots program was offset in part by a nearly 10 percent decline in revenue at Hollywood Casino in Perryville compared to the previous June.

The casino, which was the state’s first to open and has 1,500 slot machines, generated nearly $8 million in revenue this June, down $864,466 from a year ago.

Martino and officials from Penn National Gaming, the casino’s owner, have attributed the decline to gamblers heading to Maryland Live! instead.

“My guess is that it’s almost all attributable to Maryland Live!” Martino said.

The Casino at Ocean Downs near Ocean City, Maryland’s other open venue, posted $4.4 million in June revenue, up 16 percent from the same month last year.

Two planned Maryland casinos — in downtown Baltimore and Western Maryland — have yet to open.

The numbers for Maryland Live!’s first partial month comes as state leaders are weighing whether to hold a special legislative session on an expanded gambling plan that would allow one more casino, in Prince George’s County.

Both sides on Tuesday seized on the success of Maryland Live! to bolster their arguments.

Boosters of a Prince George's venue, most likely at National Harbor, said the numbers showed there was a large enough appetite for gambling to justify another casino.

But Weinberg cautioned that additional competition undercut the market for Maryland Live!. He said about half the casino’s patrons in June came from the District and its suburbs in Maryland and Virginia.

“It is clear that if we are going to continue to meet the state’s expectations, we have to be able to continue to draw visitors from these areas,” Weinberg said.