You will require the appropriate visa and the type of visa required will depend on the reason for the move.
If you wish to work, you will require an employment based visa. It is important to note that the U.S. government, unlike some countries, does not offer casual work visas. Visas are based on a specific job offer. A list of the various types of temporary work visas with a step-by-step guide on obtaining a visa, is available from our website at http://uk.usembassy.gov/visas/
If, however, you wish to remain in the United States for an indefinite period, you will require an immigrant visa; it is not possible to enter the United States on a nonimmigrant visa if your intention is to take up indefinite or permanent residence.
Immigrant visas fall into two very general categories, family reunification and employment based. It is important to note that an immigrant visa is required whether you wish to work or not. A list of the available immigrant visa categories is provided on our website at http://uk.usembassy.gov/visas/
If you don’t have any relatives who qualify to sponsor you, and you are unable to immigrate through employment, you may be interested in the Diversity Visa Program, commonly known as the Green Card Lottery. Information about this program is available from our website at http://uk.usembassy.gov/visas/diversity-visa-lottery/
Note, the Diversity Visa Program is not generally open to those born in the UK, and eligibility to enter is based on place of birth, not nationality.
The opportunity to register for the Diversity Visa Program reoccurs every fall when the DV eligibility criteria and entry instructions are being announced. Don’t believe anyone who tells you otherwise! Regularly check our tips at http://specialrelationship.uk/category/travelvisas/ to help you avoid getting caught out by DV scammers.
Updated February 11, 2016.