Washington’s primary election season is under way, and counties around the state began sending ballots to over 4 million voters at the start of this week.

Voters will have until Aug. 2 to fill out their ballots and return them via drop boxes, by mail, or in person to the county elections office. In-person voter registration is available until this Monday, July 25, for those not currently registered. About 65,000 military and overseas ballots were mailed out by June 18, with many of them already cast and returned to their home counties.

This is the big once-every-four-years election, said state Elections Director Lori Augino in a release. Voters are choosing finalists for all nine statewide elected officials, including governor, and five of the incumbents are not seeking re-election: lieutenant governor, treasurer, auditor, lands commissioner and superintendent of public instruction.

Washington also will winnow the field for U.S. Senate seat now held by Patty Murray. All 10 U.S. House seats are up this year, and most of the State Legislature is on the ballot as well, including all 98 House seats and 26 of the 49 Senate positions.

The ballot is loaded with dozens of races as voters narrow the field for each office to two top vote-getters who will advance to the Nov. 8 General Election. According to the Washington Secretary of State’s office, 671 candidates total are running for federal, statewide, legislative, county, judicial and local offices, and hundreds more are running for Democratic and Republican precinct committee officer positions.

One nonpartisan state Supreme Court race, for the seat now occupied by Chief Justice Barbara Madsen, will be on the Primary ballot. Two other incumbent justices have a lone challenger and will not be on the ballot until the General Election.

The top two primary winners seeking each office will advance to the General Election, without regard to party. Voters do not register by party and may vote for their favorite for each office.

The presidential candidates will appear on the November ballot. Washington had input through Presidential Primary and caucuses held earlier. Under state law, the Republican and Democratic national nominees automatically go to Washington ballot, while minor party or independent tickets are qualifying by gathering 1,000 voter signatures at conventions to be held no later than July 23.

Statewide ballot propositions also will be voted on in the fall election.

According to Secretary of State data, the last comparable elections, in 2012 and 2008, had turnouts that averaged 41 percent, with a General Election average turnout of double that at 82 percent.

“This primary is an important opportunity for the voters to express themselves on the leaders who will guide the state and our communities in the coming years,” Secretary of State Kim Wyman said. “I know people are really engaged in this highly unusual election year, and I’m hoping they will use their ballots as a means of expression.”