Visit the MT Secretary of State's website and look yourself up.
You'll need to enter your first name, last name, and date of birth. You'll need to type in your name without spaces or punctuation. If your name can't be found, you may not be registered to vote.
Check the address where you're registered.
Make sure the address where you are registered is your current address. This ensures you are able to vote for the correct local representatives for the area where you live. Some elections, such as local elections, are conducted by mail, so checking that your address is up-to-date will ensure your ballot is mailed to the right place. Ballots will not be forwarded.
Check to see if your voting status is "active" or "inactive."
If your voting status is "inactive," and your county is conducting a mail ballot election, you will not automatically receive a ballot in the mail. Even if you are "inactive", you are still considered registered and can vote! You will just need to contact your county elections office to re-activate your registration and be mailed a ballot, or you can vote in-person.