Is it correct to say: "sell/send/distribute throughout the United States."? The idea is that the person/firm sends/sells/distributes something to every city in the United States. I really want to use 'throughout' and I'm not sure which verb is suitable in that case.
Throughout the United States means everywhere in the United States. It works with any verb that might reasonably be used with that meaning. There are no special requirements for verbs to work with throughout.