A few thousand voters in Arlington County and Alexandria will have a different precinct this year thanks to the Virginia General Assembly’s redistricting plans.

Alexandria gained a state senator in the West End but lost one House of Delegates seat in the north. Arlington gained more representation in the Senate, but the new 32nd District stretches from the west corner of the county to Reston.

The new state districts in Alexandria have “no significant impact” on the city, said Mayor William D. Euille (D). But the additional seats in Northern Virginia are welcome, he said.

“We never feel we get fair representation in Richmond,” he said.

The new districts are “job security gone way awry,” said Jim Pebley, an Arlington civic activist.

“If you got more people, you ought to have more representation,” he said. “They were going down the road to get more representation, and they drove the car in the ditch.”

New districts are drawn every 10 years based on data from the census to ensure voters are equitably represented on local, state and federal levels.

The 30th Senate District, which covers the eastern side of Alexandria and runs into south Arlington, was recently vacated by Sen. Patricia S. Ticer (D-Alexandria). Del. Adam P. Ebbin (D-Arlington), City Council member Rob Krupicka (D) and Arlington School Board chairwoman Libby Garvey have announced their candidacy.

The 35th and 39th Senate districts now represent western Alexandria.

Senate Majority leader Richard L. Saslaw (D-Fairfax) holds the 35th District.

Incumbent Sen. George L. Barker (D-Fairfax) will face a Republican challenger this year: either M. Miller Baker or Scott M. Martin in the 39th District. This district, which runs into Prince William County and Manassas, is the most Republican district in Alexandria and Arlington. Nearly 53 percent of the voters in this district cast ballots for Gov. Robert F. McDonnell (R), according to statistics from Virginia Public Access Project.

Central and north Arlington are part of Senate District 31, which stretches to Great Falls. The open seat, formerly held by Sen. Mary Margaret Whipple (D-Arlington), has two Democratic candidates — Arlington County Board member Barbara Favola and lawyer Jaime Areizaga-Soto — and one Republican candidate, Caren D. Merrick.

The 32nd Senate District, held by Janet D. Howell (D-Fairfax), stretches from the western corner of Arlington through McLean to Reston. Patrick Forrest (R) announced his run for Howell’s seat this week.

Alexandria Democrats Del. Charniele L. Herring in the 46th District and David L. Englin in the 45th District represent the west and east sides of the city, respectively. Englin’s district also runs into Arlington, covering the area around Fort Scott Park.

Del. Patrick A. Hope’s (D-Arlington) 47th District still covers the western and central portions of Arlington. Del. Robert H. Brink’s (D-Arlington) 48th District along the north and east ends of the county narrowed.

The 49th District, formerly held by Ebbin, remains in the county’s south. Democrats Stephanie Clifford and Alfonso Lopez have announced their candidacy.

Mike Lieberman, chairman of the Arlington County Democratic Committee, said the new districts “strengthen your resolve to redouble efforts” during elections but also said he was confident the party would be successful.

Two House districts and one Senate district in Arlington were split between precincts, which is not allowed by law. Boundaries are being adjusted at Oak Ridge, Jefferson and Ballston, said Linda Lindberg, Arlington County’s general registrar. A public hearing on the moves will be held in June.

Two election precincts in Alexandria, Cora Kelly and Lee Center, are being reduced to better manage election day, said Tom Parkins, Alexandria’s general registrar.

“We’ve redrawn them in such a way where nearly everyone who is affected will be closer to their polling places than they were before” or will have a more convenient route there, he said.

A public hearing on Alexandria’s changes will be held Saturday.

All of the changes must be approved by the Justice Department, which takes about two months.