At all elections now in Wisconsin, voters must show an acceptable photo ID before a ballot will be provided.
More information on this new requirement is available here.

Registration is available on election day, but lines will be long!  Bring your Proof of Residence to the clerk’s office anytime during regular business hours, or mail in the “Wisconsin Voter Registration Application” with a photo copy of your Proof of Residence at least 20 days prior to any election to register early and avoid lines!