The largest market for regulated online gambling in the US is New Jersey. The state has over a dozen legal and licensed online casino sites and poker rooms with a combined market that's worth $225+ million a year
Tennessee provides an example of just how popular online sports betting is in the US. Even though the state has no physical gambling venues, in 2019 it approved a law that allows for online sports betting only. Their first sports betting sites launched in late 2020.
The COVID-19 pandemic has been a significant market driver in this space by resulting in many live sports events being shut down, which has driven many sports fans to seek out or increase their sports betting activities.
In 2018, the US Supreme Court legalized sports betting, opening the door for ongoing growth of online sports betting.
Now online/mobile already accounts for upwards of 80% of all wagers placed online in states that allow sports betting
..the rapid legalization of sports wagering across the United States has not relented, which has fueled continued prosperity for gambling operators and related companies.