The box office at Capital One Arena in Washington is being transformed into a sportsbook, complete with betting windows and self-serve kiosks, and will begin taking cash bets Friday, a first for an American sports venue.

Beginning at 4 p.m., Friday, bookmaker William Hill U.S. will operate seven betting windows and nine kiosks at the arena's box office, taking wagers on professional and collegiate sports.

The box office will serve as a temporary space while construction on a permanent sportsbook inside the arena continues. In the meantime, the sportsbook will be open seven days a week with normal operating hours of 11 a.m. to 11 p.m. The sportsbook entrance is located at 601 F Street NW, between Sixth and Seventh streets.

COVID-19 safety protocols, including social distancing, will be in place at the sportsbook, with hand sanitizer readily available and William Hill staff wearing masks and gloves and disinfecting kiosks after each customer.

Capital One Arena, home to the Washington Capitals of the NHL and Washington Wizards of the NBA, will become the first professional sports venue in the U.S. to have betting windows and kiosks. It also will be the first physical sportsbook in the District of Columbia. (The D.C. Lottery launched a mobile betting app in June.)

In October, Monumental Sports & Entertainment founder Ted Leonsis, owner of the Capitals, Mystics and Wizards, announced a partnership with William Hill and plans for a multifloor sportsbook inside Capital One Arena. William Hill is targeting this fall for completion of the permanent sportsbook.

"Bringing fresh and innovative experiences to fans is core to our mission at Monumental Sports & Entertainment, and we are so proud to partner with William Hill to bring this new dimension to the Washington Metropolitan region," Jim Van Stone, president of business operations and chief commercial officer for Monumental Sports, said in a release announcing the opening of the temporary sportsbook.

"William Hill is a globally-recognized brand in delivering excellence and is an industry leader in safe, responsible gaming while maintaining the highest levels of integrity. Those qualities are consistent with our own values, and we look forward to inspiring even more visitors to our arena, where we take deep pride in fostering a sense of community."

"We are proud of our relationship with Ted Leonsis and his team at Monumental," Joe Asher, CEO of William Hill U.S., said in the release. "They have been terrific partners, and we're really pleased with how we have worked together to navigate through this challenging time. We've come up with this temporary location as a way to allow our customers to bet on sports now that they are resuming, while we continue to work towards finalizing the permanent sports book, restaurant and bar concept we have always visualized."

The box office sportsbook at Capital One Arena will not offer a seating area. There will be one line for the betting windows and one line for the kiosks, with attendants directing customers to available stations. TVs, hanging above the betting windows, will display the odds and point spread.

William Hill will host an opening ceremony at 11 a.m. Monday, when three first-year season-ticket holders for the Capitals, Mystics and Wizards will make ceremonial bets.

The permanent sportsbook will be a two-story space inside the arena in an area previously occupied by the Green Turtle restaurant. It will be open during professional games once teams return to their home venue, although the court or rink will not be visible from the sportsbook.

"It'll be what I think is the most immersive sportsbook-restaurant experience anywhere the country," said David Grolman, president of retail operations for William Hill U.S. "We'll have TVs obviously throughout, great lounge seating up on the second floor, and we hope that the restaurant itself will serve as a first-class restaurant, not just a place where'd you go to get wings."

For decades, U.S. professional and collegiate leagues adamantly opposed sports betting over concerns that it would negatively impact the integrity of games. The NFL, NBA, NHL, Major League Baseball and the NCAA fought a six-year legal battle with New Jersey to try to prevent regulated sports betting from expanding in the U.S. In May 2018, the U.S. Supreme Court struck down the Professional and Amateur Sports Protection Act of 1992, the federal statute that had restricted regulated sports betting to primarily Nevada. Since the ruling, legal sportsbooks have opened in 18 states and the District of Columbia, and professional leagues and franchises are entering commercial partnerships with bookmaking companies.

For example, the Denver Broncos have partnered with multiple bookmakers, including BetMGM, which will run a betting lounge at Empower Field at Mile High. Wells Fargo Center in Philadelphia also has a gaming lounge, but no betting windows or kiosks are included in those spaces.

So far, the District of Columbia and Illinois are the only jurisdictions that have passed sports betting legislation allowing bookmakers to operate at sports venues. Wrigley Field and United Center in Chicago have considered putting sportsbooks on site or near the venues, multiple sources have told ESPN.

"It's no surprise at all to have sportsbooks in stadiums and arenas," said Wayne Kimmel, a venture capitalist and chairman of SeventySix Capital Sports Advisory, a consulting group focused on the evolving landscape of sports and gaming. "I think you're going to see a complete convergence of the sports world, the sports betting world, the casino industry, all really coming together and providing a full, 360 entertainment experience for fans in the future."