HARRISBURG, Pa. — The doors are wide open to candidates for the eastern Pennsylvania congressional seat that’s being vacated by Republican U.S. Rep. Charles Dent after next year.

A Republican state lawmaker, Ryan Mackenzie, announced his candidacy Friday for the 15th District seat, barely 12 hours after Dent announced he wouldn’t run next year. Mackenzie’s been in office since 2012.

Also running is another Republican state House member, Justin Simmons, who’s been in office since 2011, and Democrat Bill Leiner, a former Lehigh County commissioner.

Dent, a former state senator, has held the seat since 2005 and is among a dying breed of centrist Republicans on Capitol Hill.

Based around Allentown for decades, Republican mapmakers in 2011 stretched the district almost 90 miles to the Susquehanna River in central Pennsylvania to make it more Republican.