Maine has seen a surge in online voter registration, with more than 10,000 voters using that method to register in September and already more than 5,000 so far in October. Online voter registration is available through Tuesday.

Just over three weeks until Election Day, states are ending voter registrations. Here's when your state's deadline and how to register online.

While some states allow same-day voting registration, the deadlines for the rest range from 3 to 30 days before an election.