Eric Jones has spent roughly $15 million of his own money trying to unseat Rep. Mike Thompson in California's 4th Congressional District, making it the largest self-funded congressional campaign in state history, according to CalMatters.

The race, which covers parts of nine Northern California counties including Napa, Yolo, Placer and Sacramento, goes before voters Tuesday, Nov. 3. El Dorado County falls outside the 4th District boundaries, but the contest has drawn heavy attention across the Sacramento region.

Thompson, 75, a Democrat from St. Helena, has held the seat since 1998. He won the June primary with 41% of the vote, The Sacramento Bee reported. Jones, 35, a former venture capitalist and fellow Democrat, narrowly advanced by edging Republican Raymond Riehle, 22.2% to 20.7%.

Riehle has since endorsed Jones and launched a group called Californians Against the Democratic Establishment to court Republican and independent voters. Those voters make up nearly 30% of the district's registered electorate, according to the Bee.

Polls and money

Two mid-October polls commissioned by the Jones campaign showed him leading Thompson by at least 10 percentage points, the Bee reported Oct. 28. No independent polling of the race has been identified.

One survey, by David Binder Research, put Jones ahead 45% to 35%. A second, by Fulcrum Strategy Group, gave Jones a 13-point edge at 53% to 40%. Both polls together reached 1,000 likely voters.

The Binder results marked a reversal from a July survey by the same firm that had Thompson ahead 40% to 28%.

Thompson's campaign manager Thomas Dowling called Jones "desperate to buy a seat in Congress" in a written statement. Jones reported $8 million in income last year, according to a financial disclosure report cited by the Bee.

Where they split

The candidates clashed at an Oct. 7 debate over data centers, affordability and health care, the Bee reported.

Jones called for a ban on data centers in California and an immediate tax on artificial intelligence companies. Thompson said communities and states should control the process and that data centers should not displace agricultural land.

On health care, Thompson pointed to his co-sponsorship of a Medicare for All bill and his position as the top Democrat on the House Ways and Means tax subcommittee. Jones proposed expanding Medicare to cover vision, dental, in-home nursing and generic prescription drugs.

Jones has pledged not to accept corporate donations. Thompson's campaign accused Jones of relying on donors outside the district, including Silicon Valley executives.

The two agreed on several issues: both supported a national wealth tax, breaking up PG&E and allowing local law enforcement to cooperate with federal immigration agents under certain conditions.

What's on El Dorado County ballots

El Dorado County voters will not see this race on their ballots. The county's voter information pamphlet lists Congressional Districts 3, 5 and 7 for local voters. The redrawn 7th District includes El Dorado Hills and Placerville, according to ABC10.

Polls open at 7 a.m. and close at 8 p.m. on Nov. 3.