During the 19th century, gambling took on a new form with the rise of saloons and riverboat casinos. The expansion of the frontier in the West brought about an increase in gambling establishments. These venues served as social hubs, offering gambling, drinking, and entertainment to cowboys, miners, and people seeking their fortunes in the new territories. However, as the United States moved toward a more morally conservative society, opposition to gambling grew. Religious groups and reform movements spearheaded the prohibition of these activities, leading to the closing of many gambling establishments.
In the early 20th century, the prohibition of alcohol fueled the growth of illegal gambling, as underground casinos and speakeasies emerged. Organized crime syndicates saw an opportunity to exploit this lucrative industry, setting up illicit gambling operations across the country. However, the tide began to turn against illegal gambling in the 1930s when the Great Depression hit. In an effort to boost state revenue, several states legalized various forms of gambling, including horse racing, lotteries, and bingo.