At present the world's most familiar online gambling jurisdictions take in the islands of Barbuda and Antigua, Khanawake (Canada), Netherlands Antilles (Curacao), Gibraltar, the Dominican Vanuatu and Republic.
Online Gambling License:
Actually there is no need to take a license in order to operate online gambling business. But why the most online casino takes a license from an online gambling jurisdiction? The reason is that they want to add credibility and legitimacy so that the online gamblers feel free to play casino.
It is something like your home vet. It's not expected to you to take your pets to a vet what have no license would you? Certainly you wouldn't.
Online gambling operations take license for the jurisdiction in order to clear the security issues by monitoring the self-governing non-profit gambling 'watchdog' associations.
This monitoring guarantees that the casino is operating their business fairly in order to protect both players and casinos.
Gambling in USA:
At present the online gambling is banned in USA. That mean's online casinos, online bingo halls, online sports betting sites and online poker rooms cannot be lawfully owned and functioned in the US.
But this law can't stop millions of US citizen from online gambling. Because stopping the US citizens from enjoying and accessing online gambling is very hard for US Government.