By 4 p.m. Monday, more than 5,000 people had already visited the casino, said Jim Brown, Hoosier Park's general manager for gaming.
"It exceeded my expectations," he said. "It was a Monday, and we had customers lining up before sunrise. Over 800 folks joined us within the first hour."
At least one person won a $25,000 jackpot on the casino's opening day, and many people who came early said they were glad to have a casino close to home.
"We just love to gamble," said Diane Voss, Anderson, who waited in line with her mother.
"We don't have to drive two hours," the 35-year-old Voss said. "It's probably too convenient."
Bonnie Storm, 50, who described herself as an "average" gambler," drove 70 minutes from Fort Wayne to play on Hoosier Park's electronic slots.
"This is fun," she said. "It's going to be exciting because it's brand new."
With the addition of the casino, Hoosier Park officials expect the site's racing, gaming and live entertainment to draw 3 million visitors to Anderson annually.
"Today, folks, Anderson has become a destination," said Rick Moore, Hoosier Park's general manager for racing, during the ribbon-cutting ceremony.
The plans that led to Anderson getting Indiana's first combined horse track and casino go back to 1990 when businessman Virgil Cook gave 140 acres to the city of Anderson for the development of Indiana's first pari-mutuel racetrack. The donation was more than half of a larger plot that Cook purchased from General Motors in the 1970s.
Cook and his wife, Maxine, attended the casino's opening. Maxine Cook bet the first official dollar about 30 minutes before the casino doors opened.
"This is what I had in mind when I bought 250 acres from GM," Virgil Cook said moments after patrons began filing into the building. "I didn't realize then that for a casino the gestation period is 20 years."
The Indiana General Assembly voted in April 2007 to allow slot machine gaming at Indiana's two pari-mutuel horse racing tracks, Hoosier Park and Indiana Downs in Shelbyville. Construction at Hoosier Park began five months later.
Indiana Downs plans to open a 70,000-square-foot temporary casino next week and a 270,000-square-foot permanent casino next year.
By last week most of the gaming machines at Hoosier Park were in place for a test day that gave Hoosier Park employees the chance to refine their service skills. The day also gave the Indiana Gaming Commission a chance to audit the casino in preparation of the official opening.
Brown said most of the roughly 600 new hires had come from the Anderson area, bringing an additional $200 million in salaries, tips and benefits to local pockets over five years.
Hoosier Park is expected to pay state and local governments close to half a billion dollars in the next five years, Brown said, with $400 million going to the state. Madison County should receive an additional $40 million, $18 million of which will go to the city of Anderson.
At the ribbon-cutting, Brown presented a check for $25,000 to the United Way of Madison County and announced that Hoosier Park was also donating $10,000 to the Red Cross and Salvation Army to assist with relief efforts for the tornado that hit Indianapolis on Friday.