Two hours after Encore Boston Harbor ceremoniously threw open its doors Sunday and welcomed gamblers to the first eastern Massachusetts casino, more than 5,000 people were still waiting in line to get into the Everett gambling palace.

Though the company did not provide estimated attendance figures for the opening day, officials from Encore and parent company Wynn Resorts said Sunday that the guests who flocked to the casino largely did so via public transportation or other alternatives to driving.

"This morning demonstrated that guests will leave their cars at home if they have access to modern and convenient choices," Robert DeSalvio, president of Encore Boston Harbor, said in a statement. "In the days ahead, we will continue to monitor traffic closely, but today we want to thank our visitors who embraced alternatives."

A company spokesman said there are not estimates of how many guests got to the casino by which means on Sunday. Guests lined up hours ahead of the 10 a.m. grand opening and 5,000 were still in line at noon, according to Wynn Resorts spokesman Michael Weaver. All guests were inside by 2:30 p.m. and players arrived "continuously all day," he said.

"We are very pleased with the attendance numbers and the overwhelmingly positive response we've received from guests about the Encore experience," Weaver said. "They recognize it truly is a new level of gaming resort on the Eastern Seaboard."

The $2.6 billion resort casino sits on 33 acres of formerly contaminated land along the Mystic River in Everett. In addition to the construction of the 671-room hotel and 210,000-square-foot gaming floor, the company spent $68 million on environmental remediation. The resort casino is expected to employ about 5,500 people.

"Eight years ago the people of Massachusetts and lawmakers had the foresight to understand that with the passing of the gaming legislation, there could be the opportunity for economic development and the finest integrated resort in the region," Wynn Resorts CEO Matt Maddox said in a statement. "I am here to tell you Encore Boston Harbor has achieved those goals."