.US is one of these generic Top Level Domains that have a recommended usage and specific purpose, but its registration is not currently restricted for anyone. The abbreviation of the ccTLD indicates the “USA”, because it was initially intended for use from entities connected with the United States. This was the main reason why the .US country-code top-level domain was established back in 1985. So, US is one of the oldest domains and the number of registered US country-code top-level domains is over 1,5 million.
.US Registration Requirements
As mentioned, the registration process for .US country-code top-level domain is now mostly open to everyone. U.S. nexus requirement can be enforced by challenge, but seldom is. So, you’d better use a .US Country Code Top Level Domain only if you want to be associated with entity residing in the United States. US can also be registered as a Second-Level Domain name. Of course, as with all TLDs, you should first check if the domain is available. If you transfer the domain, it should be unlocked and you should provide an EPP Key to your new registrar.