Can a US citizen residing in the UK start an online business in US?
I am a US citizen currently residing in the UK married to a British citizen. Can I start an online US-based business - with no physical presence in the States - from abroad?
Yes, you can register a company in the United States without being a U.S. resident. You can use your home or business address in the UK for the business address, so not having a physical presence wouldn't be a problem for you.
On any of our applications for registering a corporation or an LLC in any state, there is the option at the top of the first page specifically for international residents.
Did you have a specific state in mind? If you plan on selling products, Delaware may be a good state to consider as they do not charge a state sales tax. If you are using this for an online business that provides a service, then you may want to consider registering your business in Wyoming.