Whether you've moved and need to update your address or you're new to Montana, you have some extra time to get registered and vote, even after the regular registration deadline.
Here is the catch: you must appear in-person at your local election office to do so. Election offices are open weekdays from 8am to 5pm (except days observed for federal holidays) for late registration. Election Administrators always encourage voters to take advantage of this service sooner rather than later to avoid wait times.
Note: Late registration closes at noon the day before the election. All Montana election offices observe this noon deadline. It's the "last call" to register for the election.