Jay Davidson, the head of Baltimore Racing Development, blamed the delay on last-minute changes to the placement of grandstands along the Inner Harbor race course.
"We had to reconfigure some grandstand seats" to make them compliant with the Americans With Disabilities Act, said Davidson. "Before we sent out tickets, we had to talk to the people affected."
Organizers had said the tickets would be mailed in late May or early June, then later said they would be sent in mid-June.
Davidson said organizers decided to change to a better-quality paper for the tickets, which also contributed to the delay.
He described ticket sales, which began in early December, as "very strong," with "well over 50,000" sold.
Tickets advertised on the Grand Prix website range in price from $45 to admit an adult to the grounds on Sunday to a three-day VIP Balcony Club pass for $875.
Davidson said organizers had sold nearly two-thirds of the grandstand and 78 of 81 hospitality suites. He declined to disclose the exact number of tickets sold, saying that promoters had advised the group not to reveal that information.
"We're going to have over 100,000 people over the three days, assuming we have good weather," he said.
City officials have set aside $7.75 million to prepare two miles of streets along the harbor for the race. The Maryland Stadium Authority recently completed a $2 million project to turn a parking lot at Camden Yards into a pit lane; race organizers are required to repay that cost.
The race, which is slated to be run for the next five years, is expected to pump more than $70 million in revenue into the region, organizers say. Officials say the city should reap about $2 million in direct tax revenue from the race this year.