Californians will help determine which party controls the U.S. House, choose a successor for the state's longest serving governor, and weigh in on ballot measures to repeal a tax increase and expand rent control in this year's midterm election.
Candidates made their final pitches Sunday as campaign volunteers furiously worked to make sure their voters show up at the polls or postmark their ballots.
It's California's fourth election since voters adopted a primary system that allows two candidates of the same party to face off.
That's produced contests between two Democrats in a handful of federal and state races, showcasing the party's dominance over Republicans in the nation's most populous state.
Here's what to know ahead of Tuesday:
WHO VOTES, AND WHEN
More than 19.6 million Californians are registered to vote. That's about 78 percent of eligible voters, the highest percentage of registered voters in a midterm election since 1950.
Most California voters — more than 13 million — received mail-in ballots and more than 3 million people had cast them as of Friday, according to county data compiled by the non-partisan Political Data, Inc.
Republican, older and white voters are more likely to vote early.
As the election gets close, though, voters younger than 50 are returning early ballots at a higher rate than they did during the primary.
That's also true in Orange County south of Los Angeles, one of the biggest battlegrounds for the U.S. House.
That could be a good sign for Democrats hoping for a"blue wave," said Paul Mitchell, vice president of Political Data.
HOW THE COUNT WORKS
As long as California ballots are post-marked by Election Day and received by Friday, they will be counted.
But because so many voters cast ballots by mail, it takes weeks for every ballot to be counted.
That means the outcome of close races may not be known until well after Election Day.
Depending on how Democrats fare in the rest of the country, the nation could end up waiting on California to learn which party takes control of the U.S. House.
Orange County is experiencing an unusual amount of pre-election buzz and activity from Democrats, reflecting its importance as a national battleground for the U.S. House.
U.S. Sen. Kamala Harris and Democratic gubernatorial candidate Gavin Newsom campaigned there Saturday, while U.S. Sen. Dianne Feinstein planned to bring her re-election bid to the city of Irvine on Sunday night alongside gun control activists from Parkland, Florida.
In an upbeat Sunday morning rally, Democrats Attorney General Xavier Becerra and state Assembly Speaker Anthony Rendon told volunteers that the election hinges on Orange County. Rendon said the "entire country and the entire world" would be watching the outcome.
The county registrar of voters set up pop-up mobile voting locations, including one at a community college that hosts an outdoor market popular with Vietnamese American and Latino communities. A handful of voters waited to cast ballots early in the morning, with some saying they wanted to vote early to be sure their vote counted and avoid any Election Day lines.
THE GOVERNOR'S RACE
Republican gubernatorial candidate John Cox visited Orange County on Saturday before turning his attention to the state's Central Valley agricultural heartland, where Republicans are also defending U.S. House seats. He'll be in the capital city of Sacramento on Sunday evening to campaign with Republican U.S. Rep. Tom McClintock.
Newsom planned to stump in Los Angeles on Sunday. His giant blue tour bus is being tailed by a van declaring Newsom would bring "fraud" and "higher taxes" to California. It's run by a group called Californians for Accountability PAC funded primarily by two business owners in the oil and beverage industries.
Feinstein's rival, state Sen. Kevin de Leon, is the feature of a Sunday night rally in San Diego for the California Democratic Party.
SHOW ME THE MONEY
In California's tight battles for Congress, Democratic challengers have far outraised Republicans.
Democrats who brought in the most cash include Gil Cisneros, a lottery winner who gave himself more than $8 million; Harley Rouda, who is challenging incumbent Rep. Dana Rohrabacher; and Katie Hill, Rep. Steve Knight's opponent.
More than $367 million has poured into campaigns to support and defeat the 11 measures on California's ballot, which include eliminating restrictions on rent control, requiring cage-free eggs, and spending billions on affordable housing and homelessness prevention.
Proposition 8, which would cap the profits of dialysis companies, is by far the most expensive, with dialysis companies contributing $111 million in opposition. That's the most raised on any one side of a ballot measure in the U.S. since at least 2002. A whopping $67 million of it comes from the Denver-based DaVita Inc.
The battle over rent control, Proposition 10, is the second most expensive _ with the AIDS Healthcare Foundation's $25 million versus $76 million from the real estate industry.
Proposition 6, the gas-tax repeal, features a lopsided spending battle. Supporters raised just $5 million, while opponents including construction companies donated $46 million.