MECHANICSBURG, Pa. — Sara Agerton is the only Democrat on the seven-person borough council in Mechanicsburg — and the only woman. She won her seat in this small city outside Harrisburg by just 16 votes last year. On her way to council meetings on Tuesday nights, she drives past lawn after lawn displaying Trump signs.

But Agerton sees cracks in the Republican foundation of her hometown, and in surrounding Cumberland County.

“Mechanicsburg is a Republican town, but it’s getting closer,” Agerton, 40, said this week. “You’re seeing other towns on the outskirts taking a dive into the moderate-to-left views. Am I predicting a landslide? Absolutely not. But we’re taking back a little at a time.”

In nearby Carlisle, Democrats swept elections for borough council in 2019. Newly formed Democratic clubs keep popping up in other Harrisburg suburbs like Camp Hill, Upper Allen Township, and Silver Spring Township. And a congressional race in a district that includes Cumberland is seen as one of the most competitive in the country. The county is starting to look more like Pennsylvania as a whole, with rural areas solidly Republican, while smaller cities and more affluent suburbs are starting to trend more Democratic.

Cumberland County is also one of the fastest-growing counties in the state. Housing developments are sprouting, forcing school districts to expand. This area on the west shore of the Susquehanna River is still overwhelmingly Republican. But Democrats are slowly growing their ranks, with a net gain of 8,500 registered voters since 2016. Republicans added 6,600 in that time period. Independent and third-party voters increased by about 5,000.

» READ MORE: Republicans are trying to survive an anti-Trump wave in the Philly suburbs: ‘A lot of Democrats vote for me’

Suburban voters are getting a lot of attention in 2020. Democrats are hoping big turnout for Joe Biden in the suburbs, where Donald Trump’s presidency has soured even Republicans on their party, could overcome the president’s growing advantage in rural areas and small towns. Trump is hoping to revive his dwindling suburban support with a law-and-order message.

In Pennsylvania, the Philadelphia suburbs have become an epicenter of the Democratic Party. But the suburbs of central Pennsylvania are also seeing smaller gains, which could have an important impact in November and signal where Democrats can expand their party in the years to come.

Shifts similar to Cumberland County’s are underway in neighboring Dauphin County to the east and in nearby Lancaster County. Like in the Philadelphia suburbs, much of the Democratic energy has been fueled by women volunteering or running for office themselves after Trump’s election.

“As I remind people, there are suburbs besides the ones in Philadelphia,” said Harrisburg-based GOP strategist Christopher Nicholas. “Allentown has suburbs, Harrisburg has suburbs, Erie has suburbs, and Democrats are excited about that because they’ve gone from being an afterthought to at least having a pulse.”

Cumberland County has attracted younger families and some retirees. Parts of it have become somewhat more diverse, though the west shore is whiter and wealthier than the state overall.

“I think it’s the suburban shift of wanting to live in town, or near Harrisburg, people coming back with higher levels of education, and really getting involved in their communities,” Agerton said. “We have refugee neighbors, there’s a Spanish-speaking church behind my house, and yet, you’ll still see Confederate flags in Cumberland County.”

Trump won the county by 19 points, and despite some competitive races in 2018, no Democrats represent it in the state legislature. On the other hand, Gov. Tom Wolf and Sen. Bob Casey, both Democrats, carried the county on their way to reelection that year.

While Biden is highly unlikely to win here, even cutting into Trump’s margin could be significant in a state that was decided by less than 1% of the vote in 2016. Trump won Pennsylvania by 44,000 votes. He won Cumberland County by 22,000.

“I think the key in an election like this is the townships which are traditionally red and have held red, could you start getting those margins smaller?” said Sean Crampsie, a Democrat on the Carlisle borough council. “If you can keep chipping away and Biden ... loses by 10 points ... you don’t have to be completely dependent on the more traditionally blue counties.”

» READ MORE: Meet 24 Pennsylvania voters who will help inform our 2020 election coverage

One sign of the growing Democratic strength is the race for the 10th Congressional District.

Eugene DePasquale describes the district as a “microcosm of the country.” DePasquale, the Democratic state auditor general, is running to unseat Republican Rep. Scott Perry. The district includes all of Dauphin County (home to Harrisburg) and parts of Cumberland and York Counties.

“You’ve got Harrisburg and York. ... You have real inner-ring suburbs, outer-ring suburbs, and then some rural parts of the district,” DePasquale said. “So we kind of have it all here.”

DePasquale is running as a moderate with an independent streak, touting his work as the state’s fiscal watchdog as evidence he can take on either party.

Perry, a longtime conservative, has been an ardent defender of Trump whose reelection campaign messaging has closely mirrored Trump’s. He said he’s not worried about slight Democratic gains in places like Cumberland.

“Those votes are kind of up for grabs. People at the end of the day still want a safe neighborhood, peace of mind of knowing they can walk on the streets safely,” Perry said Monday. “You gotta go out and let them know what your position is, like whether you stand with law enforcement and kind of a civilized society — or more on the side of anarchists and people protesting in the streets.”

At a Rotary Club meeting Wednesday, Perry appeared to dismiss the existence of systemic racism in the United States. On Thursday, the former head of the York County GOP responded by backing DePasquale.

“I think there’s starting to be some shifts in mind-set. I’m really seeing it this year.” said Jean Foschi, the lone Democrat on Cumberland County’s Board of Commissioners (she holds the one seat set aside for the minority party).

Foschi said she thinks some independents and Republicans have been turned off by Republican opposition to coronavirus precautions. In May, several state lawmakers pushed the county commissioners to ignore Wolf’s mandate and reopen businesses. Foschi said she heard from constituents of all political persuasions.

“They’re very, very Republican and they appeal to their base, but people were really angered by that,” Foschi said.

» READ MORE: Trump’s path to winning Pa. runs through small Rust Belt towns — like one near Biden’s hometown

Republicans long outnumbered Democrats and independents combined in Cumberland. Now the county has about 89,000 Republicans, 62,000 Democrats, and 30,000 voters with third- or no-party affiliations.

Republicans largely downplay the Democratic gains.

“I think the big story in Cumberland County is independents,” said Republican State Rep. Greg Rothman. “As someone running for office, I’m trying to figure out who are the independents?” Rothman suspects some are state government workers who don’t want to be identified by a party and others are just fed up with the toxicity of politics.

Rothman said that while Democrats are running more candidates than in the past, they haven’t had much luck. “In 2019, the Democrats had more signs than they’d ever had and less votes,” Rothman said.

Or as Nicholas, the Republican strategist, put it: “When you look at the things that normally tell you change is coming, they haven’t happened yet. There’s no statehouse seat, no row officer.”

Shanna Danielson is hoping to change that. On her porch in Dillsburg (just outside Cumberland in York County), Danielson, a music teacher, sorted postcards for volunteers helping her campaign for state Senate. Her 6-year-old son checked in periodically from inside, where he was playing Mario Kart.

Danielson first ran for state representative in 2018 — a decision she made on the spot at an Indivisible meeting shortly after moving to the district. Her campaign wasn’t very organized then. She said this time feels different. She’s running for a seat that Democrats haven’t held since 1976.

“There’s a lot more enthusiasm and it’s all happened after 2018,” Danielson said. “We’re coming out of the woodwork. We’re organizing.”

“It just seems like certain people are a bit louder in their beliefs,” she added. I don’t feel like we’re drowning in red.”

Danielson has the backing of progressive groups, but her pitch to Republicans and independents in the district, which includes most of Cumberland, is more about local issues.

» READ MORE: A Pennsylvania county voted for Obama twice. But it’s ‘Trump Country’ now.

At a borough council meeting Tuesday back in Mechanicsburg, Agerton talked with colleagues about street sweeping and how to safely hold trick-or-treating this year given the pandemic. There was no sign of political discord among the lawmakers, who went about the city’s business wearing face masks.

Leanne Clark attended the meeting. Clark recently moved back to the area after some time away following her husband’s death. She said feeling like the political underdog in a key election is motivating. As an example, she pulled up a photo on her phone: Someone had stuck a “Trump 2020″ sticker on her Black Lives Matter sign.

“I can’t tell you how p—ed I was,” Clarke said. “I hope he doesn’t win here again. But, you know, that makes you fight harder. And there’s more of us out here than you think.”