A story Republican nominee Jack Ciattarelli tells on the campaign trail also doubles as a joke: A woman in Morris County, New Jersey, walked into a cafe and approached him “respectful but a little defiant,” he told a crowd in Roxbury, a township near the county's eastern edge.

“She said, ‘I want you to know something. Mikie Sherrill is my congresswoman, and I really liked the job that she's doing, representing me in Washington, D.C.,” he said, referring to his Democratic opponent. “And I said, 'Ma'am, that's why I'm here. You vote for me. I'll make sure she stays your congresswoman.'”

The crowd erupted in laughter.

The sprawling, high-turnout suburbs of Morris County, located 30 miles west of New York City, are arguably the most important battleground in New Jersey’s tightening race for governor, especially as turnout in urban areas has languished in recent years. The county ranks as the second-wealthiest in the state, according to a survey of household income and investments. And while it has historically gone reliably for Republicans like Ciattarelli — he won 55.3% of the vote here in his 2021 bid for governor — it has also swung toward Democrats in recent years.

Sherrill, who represents parts of the county in Congress, wasn’t just the first candidate to turn the district blue in 34 years — she flipped it by 37 points in 2018, riding a wave of female candidates who came to power during President Donald Trump’s first term in office.

“On election night, like everyone else, I’ll be looking at what happens in Morris County,” said Dan Cassino, professor of government and politics at Fairleigh Dickinson University.

Repubican Jack Ciatarelli campaigning in Roxbury, Morris County.

Pat Dennis, president of progressive political action committee American Bridge 21st Century, said the county is home to a strong population of “high-propensity voters” who dependably show up in off-year elections. In the 2021 governor’s election, Morris County had the fourth-highest percentage of voter turnout in the state, at 47%.

“ Folks who are always going to show up to vote no matter what … there's a disproportionate number of those people in Morris County,” he said.

Ciattarelli’s campaign is well aware of those figures. The former state assemblymember jokes that he’s talked with voters in all of New Jersey’s “600 diners” as he’s crisscrossed the state. But his ground game has been squarely focused on bedroom communities like Roxbury, and he's gone so far as tapping Morris County’s popular sheriff, Jim Gannon, as his running mate for lieutenant governor.

Homeownership is high here, at 73.9% compared to a national average of 65%. The Republican’s campaign platform is tailored to speak directly to homeowners’ concerns. He’s promised to lower property taxes, drive down energy prices and stop what he’s called the overdevelopment of suburban communities in their effort to meet state mandates for affordable housing — an unpopular policy among some suburbanites.

“It's important for Jack to do well here. If he does, that will give him the votes he needs to get past some of the more Democrat counties like Essex and Hudson and Camden,” said state Sen. Anthony Bucco, the top Republican in the state Legislature, who also represents Morris County. “We got to start building the momentum here to carry us through election night. And I think we're doing that.”

When asked about his chances in the county, Ciattarelli told Gothamist, “We’re going to win Morris County.”

Republican Jack Ciattarelli squared off with Democrat Mikie Sherrill at a debate on Sunday.

But Sherrill appears just as confident in her chances, and she remains popular. In a crowded and contentious Democratic primary in June, she took 62% of the vote in Morris County. She’s also led in the statewide polling throughout the race, though her lead has narrowed in recent months. The most recent poll from Quinnipiac University gives her an 8-point lead over her opponent.

“Normally you would expect Morris County would go entirely Republican, but with Mikie Sherill being fairly popular here, too, [it] may not,” said Mike Indivarry, a Roxbury resident who attended the Ciattarelli event.

Shari Seffer, chair of the Montville Democratic Committee in Morris County and a volunteer for the Sherrill campaign, said it was Sherrill’s 2018 congressional campaign that got her involved in politics. Seffer pointed to the candidate’s accomplishments in the district, including a $2 million federal grant she secured for a newly opened energy-efficient affordable housing development in Madison.

“ We in Morris County know that Mikie has given of her time and of herself to show up and to do the work,” Seffer said. “Morris County is going to be on jet fuel to make sure that Mikie Sherrill gets elected.”

Mikie Sherrill on the campaign trail.

Seffer said she’ll spend the next month canvassing and door-knocking in Morris County for Sherrill, who casts the race as part of a larger national fight over democratic norms.

“Since the American Revolution, Morris County has been at the heart of the fight for our democracy. And I know, without a doubt, that Morris County is ready to stand up for our future once again,” Sherrill told Gothamist in a statement.

Cassino at Fairleigh Dickinson University said good Democratic turnout in major urban centers could give Sherrill a “cushion” if she underperforms in suburban districts. But she can’t rely on them: Just 20% of registered voters in Newark and Paterson voted in the 2021 gubernatorial election.

Cassino said Sherrill will be in trouble if moderate Morris County voters lean Republican and turnout collapses in urban areas.

“If you see both things happening, that means Ciattarelli has probably won,” Cassino said.