Casino gaming comprises the largest segment of the commercial gaming industry. There are several types of casino gaming establishments, including Las Vegas-style casinos, which are stand-alone entities or more commonly linked with a hotel and other entertainment facilities (restaurants, bars, concert venues, etc.); dockside (permanently moored) and excursion (mobile) riverboats; card rooms (gaming establishments that exclusively offer card games for patrons); and racetrack casinos (or racinos) that consist of a casino, which typically features only slot machines, as well as either a horse-racing track, a dog-racing track, or a jai alai court. (Jai alai is a fast-paced sport that is played on a three-walled court in which a ball is volleyed at extremely high speeds by players wearing wicker-basket gloves.)

As of 2018, 41 states had some form of casino gaming. There were 351 land-based casinos, 63 riverboat casinos (not including Native American casinos), 51 racinos, 514 tribal casinos, 286 card rooms, and 16,628 electronic gaming device locations.

In 2018, there were approximately 246 federally recognized gaming tribes operating casinos in 29 states. The Indian Gaming Regulatory Act of 1988 organized tribal gambling into three classes. Classes I and II allow for traditional, or ceremonial games, bingo, and some card games. Class III allows for casino operations. Tribal nations must first enter a compact, or agreement, with the state regarding the types and regulation of games and activities they will offer. Native American gaming operations are owned, and sometimes operated, by sovereign tribes. Tribes often hire commercial casino companies to manage and operate their gaming operations. Some tribal casinos are part of larger entertainment complexes that include hotels and entertainment facilities, while others are stand-alone establishments that offer only basic bar and food service. Some of the most successful Native American casinos include the Mystic Lake Casino in Minnesota and Foxwoods Resort Casino in Connecticut.

Pari-mutuel wagering, which is legal in 43 states, is a type of gaming in which a financial prize is awarded based on the amount of money that is wagered. Horse racing (known as the “sport of kings”) is the most common form of pari-mutuel wagering. There are four types of organized racing held at licensed tracks worldwide—Thoroughbred, harness, and Quarter Horse racing takes place on flat courses, and there is no jumping; obstacle racing is held on courses with steeplechases and hurdles. While most states allow for on-track betting, some states have legalized off-track betting. As their names imply, off-track betting parlors, or OTBs, are located away from the track. Customers can bet on the day’s races via live television simulcasts. In 2018, the AGA indicated that New York was home to the most racinos, with nine. Ohio ranked second with seven locations, followed by Pennsylvania (six), and New Mexico (five). Florida, Louisiana, and West Virginia each had four racinos, and Delaware had three. Indiana, Iowa, and Oklahoma each had two racing casinos, and Maryland, Massachusetts, and Michigan were states with only one location. Other forms of pari-mutuel wagering include dog racing and jai alai.

Online gaming is the “elephant in the room” in the gaming industry. It is currently illegal to offer interstate Internet gambling services in the United States—although online casino, poker, sports, and horse race gambling is legal in several states on an intrastate level. In September 2019, Play USA reported that online casinos were legal in New Jersey, Pennsylvania, and Delaware. Online casinos were expected to begin operating in West Virginia in 2020, following legislation that was passed in March 2019. Meanwhile, online poker was legal in New Jersey, Pennsylvania, Nevada, and Delaware.

A growing number of countries, such as England, Australia, New Zealand, and France, allow and license Internet gambling services. There are six types of online and mobile gaming: casino gaming, poker, betting on horse racing, betting on other sports such as baseball and football, online lotteries, and online bingo. Many consumers, including players from the United States, visit online gaming sites daily.

The game industry advocates for expansion of legal online gambling in a consistent and regulated manner that safeguards customers and the integrity of the games. Opponents of online gambling argue that easy access to gambling will contribute to cases of pathological gambling, which will damage society.

A major sports betting-related development unfolded in May 2018 when the Professional and Amateur Sports Protection Act was overturned by the U.S. Supreme Court. The 1992 federal law had prohibited states from regulating or legalizing sports betting, with the exception of Nevada, Oregon, Delaware, and Montana, where it was already legal when the law was enacted. Nevertheless, Americans still made illegal wagers on sporting events, amounting to about $150 billion, according to the New York Times. Sports betting was legal in eight U.S. states (New Jersey, West Virginia, Nevada, Mississippi, Delaware, Rhode Island, Pennsylvania, and New Mexico) in August 2019, according to Legal Sports Report, which explained that the Supreme Court decision had created an expansion in legal betting activity. The AGA reported that legalized sports wagering increased from $261.3 million in 2017 to $430.2 million in 2018.

Greyhound racing continued to decline in favor at the end of the decade. According to the AGA, live greyhound racing was only allowed in six states prior to November 2018. At that time, Florida voters passed an amendment to ban greyhound racing by the end of 2020. However, racetracks would be allowed to maintain electronic gaming devices and card rooms and accept bets on races in other states. The Florida ban likely would have a significant economic impact, considering that the state was home to 12 of the United States' 17 dog tracks.