Quote:
The United States. Hope that helps.
For instance it would not be fair for a person living in New York, to drive out to California and vote for a governer of senate member in california. So if one moves from New York to California they would have to "register" in California and vote at a specific place and time. Otherwise it would be hard to manage 229,000,000 voters in their respective states and districs.
//Edit In many states you are registered when you get or update your driver license information. That is your voter ID card.