Business on Mill Street in downtown Orono are pictured on Sept. 3, 2021. Credit: Linda Coan O'Kresik / BDN

Republicans and Democrats put forward their plans to redraw the 35 Maine Senate districts on Thursday, with the potential to create more battleground districts in the greater Bangor area or shore up districts for incumbents depending on which maps prevail.

The party caucuses released separate proposals just over a week ahead of the redistricting commission’s deadline. Some districts that did not see significant population change over the past decade will likely remain the same. The boundaries of the current Senate District 9, which is comprised of Bangor and Hermon, remains unchanged under both the Democrat and Republican proposals. Waldo County also remains its own district.

But more drastic changes are needed in northern Maine due to significant population loss in Aroostook County, as well as in southern Maine, as some Portland suburbs saw their populations grow by more than 10 percent in the past decade.

The Aroostook County district currently represented by Senate President Troy Jackson, D-Allagash, had the lowest population of any of them, according to census data. Both caucuses proposed moving Fort Fairfield, a town of more than 3,000 people on the Canadian border, into Jackson’s district. Republicans also proposed moving neighboring Easton over.

The other northern Maine district, currently represented by Sen. Trey Stewart, R-Presque Isle, adds several more Penobscot County towns including Millinocket, East Millinocket and Medway under both the Democratic and Republican plans.

Many other Penobscot County towns could also end up in new districts. Republicans proposed moving Orono into the district currently held by Sen. Stacey Guerin, R-Glenburn, a change that would make her safe district more competitive, while adding much of the district north of Bangor currently represented by Sen. James Dill, a term-limited Democrat from Old Town, into a conservative district that would also include all of Piscataquis County.

Democrats proposed changes to the district currently held by term-limited Sen. Kim Rosen, R-Bucksport, moving some northern towns into Dill’s district and adding towns south of Bangor. Rosen’s district would remain solidly Republican, but it would move Bangor-area pieces into Dill’s former district, which would also include Orono and could be competitive.

Parties faced different challenges drawing maps in southern Maine, where population growth means most districts will be geographically smaller. Republicans, who currently hold just one seat in Cumberland and York counties combined, suggested changes that would keep the district represented by term-limited Sen. David Woodsome, R-Waterboro, relatively safe while packing together strongly-Democratic leaning towns to create additional competitive districts.

Democrats’ proposal would likely leave Woodsome’s district solidly Republican but offer fewer opportunities for Republicans to make inroads elsewhere in York County.

Neither party released detailed enough information Thursday to determine exactly how they planned to split Portland and a handful of other cities and towns that are likely to be divided across districts. The Democratic proposal involves splitting Portland, Westbrook and Scarborough. Republicans keep Westbrook together but split the town of Gray as well as unorganized territory in northern Penobscot County.

Legislative districts are supposed to be drawn to be within 5 percent of the median district population, with a minimum population for Senate districts of a bit shy of 37,000 and a maximum population of about 40,870.