Republicans will select their nominee for the late Rep. John Murtha's (D-Pa.) seat on March 11.
The meeting will be held in Latrobe, Pa., with the winner needing to get a majority of votes from party conferees from nine counties. The GOP field remains stagnant for now, with 2008 nominee William Russell and businessman Tim Burns running.
The special election is set for May 18, and Democrats are still sorting out how they will nominate their candidate.
Democrats say their state executive committee will make the final choice on their nominee, likely by March 9, but the counties in the 12th district will get to weigh in before that.
The Democrats running include former Murtha aide Mark Critz, state Treasurer Barbara Hafer, former Lt. Gov. Mark Singel, Cambria County Controller Ed Cernic Jr., Westmoreland County Commissioner Tom Ceraso and Navy veteran Ryan Bucchianeri.