The deadline to register to vote in the May 21 municipal primary and special election is April 22. In addition to the primary, special elections to represent the 11th District, which covers Butler County, in the state House of Representatives and the 41st District in the state Senate, which includes Armstrong, Butler, Indiana and Westmoreland counties, are on the ballot.

People can register through the state online voter registration website. More information is available at the Department of State website votesPA.com.