The Pennsylvania Supreme Court on Monday scheduled oral arguments for next month in its Philadelphia courtroom on 13 appeals to the new map of state legislative districts.
Challengers include the state Senate's Democratic members.
The Legislative Reapportionment Commission voted 4-to-1 in early June to approve the plan. The current version was produced because the Supreme Court threw out the previous plan in January, citing too many split municipalities and districts that were not sufficiently compact.
In the Senate, the current plan calls for the district of Sen. Jim Ferlo, D-Allegheny, to absorb a large chunk of the area represented most recently by Sen. Jane Orie, R-Allegheny, now serving a public corruption prison sentence.
As a result, her district was moved to the fast-growing Poconos region on the opposite end of the state.
Senate Democratic Leader Jay Costa has said the Senate map split counties to help Republicans retain their comfortable majority in the chamber.
The commission consists of the floor leaders of both parties in each chamber, as well as senior Superior Court Judge Stephen McEwen, appointed by the Supreme Court after the other four members could not agree on a chairman.
The high court also said the Sept. 13 session will be broadcast live on the Pennsylvania Cable Network. Seats inside the courtroom, located in Philadelphia City Hall, will be parceled out on a first-come, first-served basis.
Legislative races in the November election are being conducted with district lines for 50 Senate and 203 House seats that date back more than a decade.