**Yes—a UK citizen can potentially visit the USA for six months, and sometimes longer, by obtaining a B-2 visitor visa.** The 90-day limit applies to entry under the Visa Waiver Programme using ESTA. Those stays generally cannot be extended. [U.S. State Department](https://travel.state.gov/content/travel/en/us-visas/tourism-visit/visa-waiver-program.html)

For a longer holiday:

- **Apply before travelling for a B-2 tourist visa**, often issued as a combined B-1/B-2 visa. Complete Form DS-160, pay the application fee and arrange a visa interview. You’ll need to demonstrate your travel purpose, how you’ll fund the trip and your intention to return home. Evidence could include savings, employment and family ties in the UK. [Visitor visa application guidance](https://travel.state.gov/content/travel/en/us-visas/tourism-visit/visitor.html)
- **Six months is the usual admission period for a B-2 tourist.** The border officer decides whether to admit you and for how long. Check the departure deadline on your I-94 arrival record; the visa’s expiry date does not determine how long you can stay. [Visitor regulations](https://www.ecfr.gov/current/title-8/chapter-I/subchapter-B/part-214/subpart-A/section-214.2), [State Department guidance](https://travel.state.gov/content/travel/en/us-visas/tourism-visit/visitor.html)
- **A year is legally possible, but approval is discretionary.** The regulations permit initial admission for up to one year. If admitted for six months, you can request an extension of up to another six months using Form I-539 before your authorised stay expires. You must explain the reason, show that the visit remains temporary and explain how you’ll support yourself. Plan around the possibility of refusal. [Visitor regulations](https://www.ecfr.gov/current/title-8/chapter-I/subchapter-B/part-214/subpart-A/section-214.2), [Extension guidance](https://www.usa.gov/extend-visa)

A visitor visa does **not permit employment in the USA**. If your plans involve working or formal study, you’ll need the appropriate visa. Also, a short trip to Canada or Mexico generally does **not reset the ESTA 90-day allowance**. [Visitor restrictions](https://travel.state.gov/content/travel/en/us-visas/tourism-visit/visitor.html), [Visa Waiver Programme rules](https://travel.state.gov/content/travel/en/us-visas/tourism-visit/visa-waiver-program.html)