Many Hawaii residents will get a new representative in the state Legislature later this year — even if their current representative is running for reelection and wins.

That’s because reapportionment for all 51 House and 25 Senate districts finalized in January has shifted numerous district boundaries so that some voters in many neighborhoods now reside in a different electoral district.

For instance, people who live in Waikane and Kaaawa, currently represented by Rep. Sean Quinlan in what had been House District 47 over the past decade, are now in House District 48, which also covers Kahaluu and parts of Kaneohe, where incumbent Rep. Lisa Kita­gawa is running for reelection.

In Leeward Oahu seven House districts now exist, compared with six previously, presenting changes for residents living in Ewa Villages, Kalaeloa, Ko Olina and part of Maili.

In Central Oahu, part of Mililani is now in a different district.

In perhaps the biggest change in the state from reapportionment, Hawaii island gained one new House district, which was accommodated by reducing by one the number of districts on Oahu in order to maintain the same number of representatives in the Legislature.

The elimination of the one Oahu House district was broadly absorbed by many boundary changes.

Another result of reapportionment this year is two separate Aug. 13 primary election contests in which a pair of incumbents who now live in the same district are pitted against each other. One of these contests is for a Hawaii island Senate seat, and the other is for an Oahu House seat.

All the boundary line shifts statewide — made once every 10 years using the latest U.S. Census population data — are part of a constitutional requirement to ensure that each state lawmaker represents a fairly balanced number of residents.

The re- balancing was completed in January after nearly a year of work by the nine-member Hawaii State Reapportionment Commission, which also redrew congressional district boundary lines.

Scott Nago, chief election officer at the Hawaii Office of Elections, said a large majority of residents won’t be affected by district boundary changes.

“For the most part, voters won’t see a change,” he said.

Still, a significant number of voters across the state may be surprised to see that where they live is now part of a different district, with a different candidate or candidates running for election to represent them.

In past reapportionment years, redrawn district boundaries caused complications for some voters who went to their old polling places to vote. This year, that isn’t an issue because ballots are being mailed to all registered voters, who can return ballots by mail or drop them off at one of several voter service centers.

If voters want to see which candidates are running in their district before receiving a ballot in the mail, they can visit elections.hawaii.gov and click on the “View my ballot” link, then enter their address. The result could present new choices for voters picking lawmakers.

One example of this is in the new House district on Hawaii island, which roughly runs from the middle of Kailua-Kona down to Honau­nau after going around some of Captain Cook. People living in this area are currently represented by either Rep. Nicole Lowen or Rep. Jeanne Kapela.

For the upcoming election, Lowen, who lives in the Kailua-Kona area, estimates that around 60% of her current constituents will remain in her district if she is reelected.

“My old district kind of got split in half,” she said.

Kapela, who lives in Captain Cook, if reelected would no longer represent part of Kailua-Kona, Keauhou or Kealakekua and would retain constituents in only part of Captain Cook. She also would keep constituents in Ocean View near the southern tip of the island and gain new constituents in Volcano, Mountain View and part of Keaau on the east side of the island.

“It’s a really funky map,” Kapela said. “They drew the line literally right below my house.”

To drive from one end of this amended district to the other would take three hours, according to Kapela. “It’s quite big,” she said.

The new district between where Lowen and Kapela live has attracted five candidates — three Democrats and two Republicans.

In the Senate, redistricting is pitting two incumbents on Hawaii island, Sens. Laura Acasio and Lorraine Inouye, against each other in the Democratic primary election to represent Hilo and some neighboring areas.

Acasio currently represents most of Hilo, while Inouye’s current district stretches from North Hilo upward to Hamakua and across to the other side of the island past Waimea to Waikoloa, Kohala and Kona.

Reapportionment primarily moved the North Hilo boundary of Inouye’s current district about five miles north to Paukaa, where Inouye has lived for 29 years.

Inouye said the change makes good sense in her view because reapportionment 20 years ago split Hilo.

“That was strange,” she said of the 2002 boundary change.

This year’s election will be the second time in three decades that Inouye has had to face off against another incumbent in the Senate because of reapportionment.

The 2002 redistricting resulted in Inouye beating then-Sen. David Matsuura in the Democratic primary that year.

On Oahu a head-to-head Democratic primary election race between incumbents is on between Reps. Gregg Takayama and Roy Takumi.

Takayama and Takumi live less than a mile from each other in Pearl City. They were first elected to the House in 2012 and 1993, respectively. Much of the House district boundary between their homes during the past decade ran along Waimano Home Road but now jogs into a Manana neighborhood where Takumi lives.

In August some neighbors will have to choose between the two longtime colleagues.

MAPS ONLINE

The Reapportionment Commission’s report and maps showing past and present district boundaries can be found online at 808ne.ws/reapportion.