Can you register a car in a state you don't live in?

Can you register a car in a state you don't live in?
This varies from state to state.
In General, you need to have an address in the state in which you register your vehicle. For example, some people who live in New York, will rent a small apartment in Pennsylvania and use that apartment to register their vehicle as it is actually cheaper than registering the vehicle in NY.
You will need to check the specific regulations of the state you live in as well as the state you which to register the vehicle in.
In Florida you need a Florida Drivers licence to register a motor vehicle. When applying for your Florida Drivers licence a Florda address is required on the application, and this is where your licence will be posted to. No evidence is required for proof of living at the address supplied. Some states allow a straight licence swap without testing, check the Florida Dept. of Transport website. I actually got my drivers licence using my I-95 visa and Australian licence and passport, I did have to sit the 2 written tests and driving test though.