SOUTH PORTLAND — South Portland will hold a special citywide election March 12 to fill a vacant City Council seat.

District 1 City Councilor Tom Coward resigned as of Dec. 31 because he was elected in November to the Cumberland County Board of Commissioners. He is not allowed to serve in both positions.

The remaining city councilors voted Monday to hold the special election. Nomination petitions will be available next Monday. Candidates must collect between 100 and 300 signatures from registered voters to qualify for the ballot.

South Portland councilors are elected at-large so residents of all districts will participate in the vote. The winner of the March 12 election will fill Coward’s term, which expires in December 2014.