Two Turlock farmers will likely once again vie to represent the residents of U.S. Congressional District 10 on the November ballot, according to early Tuesday election results.

Republican incumbent Jeff Denham led preliminary results by 48.8 percent, followed by Democratic challenger Michael Eggman at 27.6 percent. At 9:58 p.m., Democrat Michael Barkley had 14.5 percent of the vote, followed by Denair farmer and Republican Robert Hodges with 9 percent.

"I feel great about the early results," said Eggman on Tuesday. "The results tonight give me a tremendous amount of hope for the November results.

"We're going to run a strong campaign on the issues that are important to people in the Valley, which are fixing our broken water infrastructure, protecting Medicare and Social Security, and expanding opportunities for the middle class," he continued.

Eggman also ran for Congress in 2014, losing to Denham.

The race for State Assembly District 12 was too close to call Tuesday night, with Republican candidates Ken Vogel and Heath Flora and Democrat Virginia Madueno receiving 25.1, 23.3 and 21.3 percent of early voting results, respectively. Democrat and Keyes resident Harinder Grewal had 19.1 percent of the vote as of 10:38 p.m. Tuesday, followed by Republican Cindy Marks with 11.2 percent.

California Attorney General Kamala Harris easily claimed a spot Tuesday on the November ballot for a seat in the U.S. Senate in a race that could for the first time pit two Democrats — both women and minorities — against one another in November.

U.S. Rep. Loretta Sanchez of Orange County, another Democrat, was in second place in early returns.

Meanwhile, Donald Trump easily won the late-season California Republican primary as other GOP candidates remained on the ballot even though they dropped out of the race.

Turnout was steady but not spectacular, despite a recent surge of interest that pushed voter registration to nearly 18 million people.

Democratic rivals Hillary Clinton and Bernie Sanders had both hoped to secure California in a symbolic win for their campaigns.

Clinton had a solid lead in early returns. A loss could tarnish her presidential campaign but not derail her path to her party's nomination, according to a delegate count by The Associated Press.

Clinton carried California in the 2008 presidential primary over then-Sen. Barack Obama, and she hoped another victory would be a capstone to her history-making candidacy.

Sanders wants to win the delegate-rich state to bolster his case that he is better positioned to beat presumptive Republican presidential nominee Donald Trump in the fall.

Voters also were narrowing the field for the November general election in contests for the U.S. House, both chambers of the state Legislature and numerous local races. They also approved a measure giving lawmakers authority to suspend fellow lawmakers and withhold their pay when they're accused of wrongdoing.

In the state Legislature, Republicans are trying to prevent Democrats from gaining a two-thirds majority in both chambers, which would give the party a virtual lock on political power.

In a further sign of the weakened state of the GOP in California, Democrats face the prospect of several same-party runoffs that have attracted millions of dollars in outside spending in a tug-of-war between the party's moderate and liberal wings.

California's primary has triggered a surge of interest, with voter registration hitting a primary election record of 17.9 million. The Field Poll estimates that 45 percent of registered voters will participate in the primary, about two-thirds of them by mail. Many of the late ballots cast by mail will not be counted until well after election day.

Election officials in several large counties — including Los Angeles and San Diego — described turnout as better than the 2012 presidential primary but below that in 2008.

Many new registrants are not affiliated with either party. The state Democratic Party allows them to vote in its presidential race, but they must request a ballot, and many are unaware of the rules.

— The Associated Press contributed to this report.