People formed long queues in Louisville on Wednesday as all 15,000 tickets to the memorial service honouring Muhammad Ali were distributed.
Following a private family funeral on Thursday, Ali's coffin will be transported through the streets of his hometown on Friday, before a private burial and public memorial service.
Louisville locals turned out in large numbers to get tickets to pay their respects to the three-time world heavyweight champion who died in Phoenix, Arizona, at the age of 74 after suffering with Parkinson's disease for 32 years.
Organisers said all of the roughly 15,000 tickets for the service have now been distributed.
Ten ticket booths had been set up to hand out four free tickets per person, with some people spending the night in line on camping chairs and wrapped in blankets to make sure they got tickets.
By 7am the line had snaked around the KFC Yum! Center, the large sports arena in the town where the ceremony will be held.
"Muhammad Ali memorial tix are SOLD OUT. Looking forward to remembering #TheGreatest! Service will also be streamed on our outdoor jumbotron," the KFC Yum! Center said on its Twitter account.
Louisville, the largest city in the southern state of Kentucky and home to 600,000 people, is preparing to play host to a mass public celebration of Ali's life on Thursday and Friday.
"This is part of our history and I feel like Muhammad Ali has an awesome legacy," said Andeja Tyler, who stood in line waiting for tickets. "I just want to be part of it."
Jessica Moore added: "Muhammad Ali was such an amazing person, not only as an athlete but really a humanitarian. He was the people's champion and we, being from Louisville, feel like family to him."
Former US president Bill Clinton and comedian Billy Crystal are among high-profile speakers scheduled to deliver eulogies and a crowd of 15,000 people is expected at the sports arena.
However, president Barack Obama will be absent, remaining in Washington for the high school graduation ceremony of his eldest daughter, Malia.