As of 6 p.m. ET, the Museum had drawn more than 13,000 visitors, besting by far a previous museum record of 9,500 in 1995.
"It is extremely busy," said ticket manager Katie Morris. "But it's been flowing really good. We've only had to shut down once, for about 20 minutes."
The Hall of Fame, Morris said, had five years to prepare for an event that observers predicted would be the largest of its kind. Cal Ripken Jr. and Tony Gwynn, two of the most popular players in baseball history, will be inducted into the Hall of Fame on Sunday.
But although the Hall of Fame had time to prepare, few could have anticipated the bedlam that would consume the Museum. Visitors packed the corridors, swarming around Orioles- and Padres-related memorabilia. Ripken fans were particularly visible.
"You prepare for the worst, and I think we did pretty good," Morris said. "We changed a lot of things as the crowds came, and things didn't really work."
The Museum gift shop closed its entrance line at 6:20 p.m. to prepare for its 7 p.m. closing. Not all visitors would have been able to push through by then.
Ron Simms, an usher for Washington Nationals games at RFK Stadium, drove up from Northern Virginia for nearly seven hours with his wife, Kris, to see Ripken. They were two of many people wearing Ripken gear and were seeking a pennant to commemorate the occasion.
"I think five years go," Simms said, "people started making hotel reservations."
As for the next wave? Rest assured; museum staff are already preparing. Morris said that one name hangs especially heavily on planners' lips: Derek Jeter.
"He's going to be a big one," Morris said. "He's the one that I've always heard."
Alex McPhillips is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.