By DAN TOMASELLO

MELROSE — Labor Day not only marks the unofficial end to summer, it also kicks off the official start of the midterm election season.

Voters from all four precincts will be able to cast ballots in the State Primary Election at Melrose Veterans Memorial Middle School gymnasium on Tuesday, Sept. 6. The polls will be open from 7 a.m.-8 p.m.

Democratic primary

The Democratic primary features five contested races.

While Attorney General Maura Healey is technically running against State Sen. Sonia Chang-Díaz of Jamaica Plain to serve as the Democratic nominee for governor, Chang-Díaz withdrew from the race in June.

Salem Mayor Kimberly Driscoll, State Rep. Tami Gouveia of Acton and State Sen. Eric Lesser of Longmeadow are the Democratic candidates running for lieutenant governor.

Former Boston City Councilor Andrea Campbell and labor attorney Shannon Liss-Riordan are running for the Democratic nomination for attorney general. Quentin Palfrey, who was the Democratic candidate for lieutenant governor in 2018, suspended his AG campaign on Tuesday and endorsed Campbell. Palfrey’s name will still be appearing on the ballot.

The two candidates running for the Democratic nomination for secretary of state are incumbent William Galvin and NAACP Boston Branch President and Civil Rights attorney Tanisha Sullivan.

State Sen. Diana DiZigolio (D-Methuen) and former state Transportation Secretary Christopher Dempsey are the two Democratic candidates running for state auditor. Auditor Suzanne Bump decided against running for re-election.

There are seven candidates running unopposed in the Democratic primary: Congresswoman Katherine Clark, State Rep. Kate Lipper-Garabedian, State Sen. Jason Lewis, State Treasurer Deborah Goldberg, District Attorney Marian Ryan, Middlesex County Sheriff Peter Koutoujian and

Governor’s Councilor Terrance Kennedy.

Republican primary

The Republican primary features two contested races.

Former State Rep. Geoff Diehl and Wrentham businessman Chris Doughty are running for the GOP nomination for governor, and are looking to succeed outgoing Republican Gov. Charlie Baker. While former President Donald J. Trump has endorsed Diehl, House Minority Leader Bradley H. Jones Jr. (R-North Reading) informed the Melrose Weekly News that he will be voting for Doughty in the State Primary.

“While I have not formally endorsed any Republican candidate for governor, I voted for Chris Doughty at the Republican State Convention and will be voting for him in the Sept. 6 State Primary,” said Jones.

Former State Rep. Leah Allen of Danvers and former State Rep. Kate Campanale of Spencer are running for the Republican nomination for lieutenant governor. Allen is running with Diehl while Campanale is running with Doughty.

There are four candidates running unopposed in the Republican primary. Former United States Postal Service Senior Operations Manager of Caroline Colarusso of Stoneham is running for Congress. Wakefield Town Councilor Edward Dombroski Jr. is looking to serve as state Senator.

Cape Cod attorney James McMahon is running for attorney general. Nashua, New Hampshire-based WSMN radio host Rayla Campbell of Whitman is looking to serve as secretary of state. Isabella Stewart Gardner Museum Security Director Anthony Amore is looking to serve as the commonwealth’s next state auditor.

There are no GOP candidates running for State Representative, Governor’s Council, Middlesex district attorney, Middlesex County sheriff and state treasurer.