JUNEAU, Alaska (AP) — The Matanuska-Susitna Borough is suing the Alaska Redistricting Board over recently drawn legislative boundaries that it says dilutes the votes of borough residents.

The lawsuit — brought on behalf of the borough and Michael Brown, the borough manager — was filed Thursday, their attorney Stacey Stone said. The case did not immediately show up on the court’s online records system.

The board finalized its maps Nov. 10, triggering a 30-day period in which challenges could be filed. The board was charged with rewriting Alaska’s political boundaries following the 2020 census.

The lawsuit cites concerns with the degree to which the target population for House districts was exceeded in the region and says two shared districts, with Valdez and parts of the Denali Borough, ignore “logical, municipal, and natural boundaries.”

Peter Torkelson, the board’s executive director, said the board “will review any legal challenges with our counsel and then respond through the court system as contemplated by the Alaska Constitution. It would not be appropriate for us to comment further at this time.”

A plan proposed by the Matanuska-Susitna Borough included four full House and two shared House districts. It did not seek to be paired with Valdez in one of the shared districts. Officials with the borough and Valdez argued against such a pairing.

The borough also proposed a shared district that included the entire Denali Borough but the plan adopted by the board excluded a portion of the Denali Borough including Cantwell, the lawsuit states.

The board’s final plan “raises an inference of intentional discrimination, by unnecessarily dividing the MSB in ways which dilute the effective strength of MSB voters,” the lawsuit states, with MSB referring to Matanuska-Susitna Borough.