Upvote:8
This is an expansion of Nicolas' comment.
In general, if you have criminal record of any sort, then apply for a visa for that country, and DO NOT LIE on your application.
For the Check if you need a UK visa page, if you plug in visitor from the USA, and for tourism, it eventually says you can travel visa free. However, it adds the following caveat:
You may want to apply for a Standard Visitor visa if you have a criminal record or youβve previously been refused entry into the UK.
Note that the Visit the UK as a Standard Visitor page says:
The earliest you can apply is 3 months before you travel.
and
Once youβve applied online, proved your identity and provided your documents, youβll usually get a decision on your visa within 3 weeks.
Which is actually a bit misleading, as they also say
Visit visas, including standard visitor visa applications, are currently taking on average 6 weeks to process, however some applications might take longer. We are working hard to process applications to get back to the 3-week service standard.
Finally, it also says:
As part of your online application, you need to book an appointment at a visa application centre.
And finally, finally. Having a visa is not a 100% guarantee of being admitted to the UK. The agents of the UK border force will have the final say about letting you into the country when you arrive on and show them the visa in your passport. They have the power to deny you entry.