PIERRE, S.D. (AP) – South Dakota lawmakers voted mostly along party lines Monday to redraw the boundaries of the state's 35 legislative districts with a plan minority Democrats said will put them at a disadvantage in elections for the next decade.

Republicans, however, insisted the redistricting plan was fair and not intended to give their party an advantage.

“Most of us put politics aside and did what is best for the people of South Dakota,” said Senate Republican Leader Russell Olson of Wentworth, a co-chairman of the Republican-dominated committee that put the plan together during meetings held over the summer and fall.

“I'm very proud of the fact that we could have been more partisan and chose not to be,” Olson said.

Assistant House Democratic Leader Mitch Fargen of Flandreau said he is happy with most of the new districts, but believes boundaries in three areas – the northeastern corner of South Dakota, Sioux Falls and Rapid City – were drawn “for the benefit of the Republican Party of South Dakota and not the citizens of South Dakota.”

The Legislature must redraw the boundaries of legislative districts every decade to reflect population changes reported by the census. The ideal district would contain 23,262 people, but courts have said each district can vary by 5 percent above or below that number.

Republicans were able to dominate the redistricting process because they have a 30-5 edge over Democrats in the Senate and a 50-19 advantage in the House, which also has one independent. The plan was approved 50-18 by the House and 31-4 in the Senate, with both votes falling largely along party lines.

Each district elects one senator and two House members at large, except for two Senate districts that are split into two House districts, each of which elects its own House member. Those single-member House districts were created to give American Indian voters a better chance to elect candidates of their choice.

The debate in both chambers focused on Democratic plans to change districts in northeastern South Dakota, Sioux Falls and Rapid City. All the proposed changes were defeated in a series of party-line votes.

Democrats sought changes in the northeastern corner of the state because the Republican plan throws five incumbent Democrats into a district that could only elect three lawmakers.

The new District 1 includes Roberts, Marshall and Day counties and the northern part of Brown County. It throws together Sen. Jason Frerichs of Wilmot, Rep. David Sigdestad of Pierpont, Rep. Dennis Feickert of Aberdeen, Rep. Susan Wismer of Britton and Rep. Paul Dennert of Columbia, who is term-limited in the House and would have to run for the Senate to remain in the Legislature.

Another district includes most of Aberdeen, the state's third largest city. A third district puts the rest of Brown County with part of Spink County and all of Clark and Hamlin counties.

Elaine Elliott, D-Aberdeen, said Brown County should be split into only two districts, not three. Democrats unsuccessfully proposed changing District 1 to cover Roberts, Marshall and Day counties and the rural portion of Codington County outside Watertown. The Aberdeen district would have remained roughly the same, but the third district would have included all of Brown County outside Aberdeen, part of Spink and Hamlin counties and all of Clark County.

The plan would have separated rural areas from the city of Aberdeen and created more compact districts than the Republican plan, Elliott said.

But Olson said during the Senate debate that the Republican plan was better because it didn't split Hamlin County into two districts.

Rep. Suzy Blake, D-Sioux Falls, sought unsuccessfully to change the boundaries of two districts on the southern edge of Sioux Falls. Blake, who represents District 13, said Republicans now outnumber Democrats by about 700 voters in her district, but the new plan gives Republicans an edge of about 2,300 voters.

“I'm disappointed, shocked and angry,” Blake said.

But Rep. Jim Bolin, R-Canton, said the GOP plan creates compact, symmetrical districts that make sense.

Democrats also proposed putting all of North Rapid City into one district. About 25 percent of the area's population is Native American, and the plan would have given them a better chance of electing lawmakers they support, Democrats said.

But House Republican Leader David Lust of Rapid City said the GOP map is better because it tries to keep districts within the city as similar as possible to current districts. North Rapid City residents don't appear to be upset with how their current legislators are voting, he said.

Residents and lawmakers from Bon Homme County tried to prevent that county from being split into two districts, but the House and Senate rejected that proposal after opponents said it would result in odd-shaped districts in nearby areas.

Under the plan that passed, most of Bon Homme County will be in a district with Douglas, Hutchinson, Hanson and McCook counties to the north. The western part of Bon Homme will be in a district with Charles Mix, Gregory and Tripp counties to the west.