(NewsNation) — Voters in seven swing states will determine the next president of the United States, but it’s counties that will ultimately tell the story of the 2024 election.

Some, like Erie County, Pennsylvania, and Kent County, Michigan, are battlegrounds within battlegrounds — bellwethers that could reflect the broader pulse of the nation. Both are areas that former President Donald Trump and Vice President Kamala Harris feel they can win.

In other places, like Wake County, North Carolina, and Wayne County, Michigan, it’s not a question of who will win but by how much.

Harris hopes to run up the score in highly populated urban areas, while Trump will try to extend his lead in rural counties and win back suburbanites who have shifted left in recent elections.

At least, that’s the narrative today — something completely different could happen on election night.

“It doesn’t matter what order you put a jigsaw puzzle together, the image will be the same at the end, whichever piece you put in, first or last,” said Chris Stirewalt, NewsNation’s political editor.

Here’s how the puzzle could come together for Harris and Trump in the key battleground states: Arizona, Georgia, Michigan, Nevada, North Carolina, Pennsylvania and Wisconsin.

Arizona

Maricopa County, highlighted above, is one of the largest voting jurisdictions in the nation.

What happened in 2020?

Joe Biden: 49.36%

Donald Trump: 49.06%

Joe Biden became the first Democrat to win Arizona since Bill Clinton in 1996 and only the second since Harry Truman in 1948. He was able to flip the longtime Republican stronghold with strong support from college graduates and Latinos — a group that accounts for nearly 1 in 4 voters in the state.

What do the current polls show?

According to Decision Desk HQ, Trump has a 59% chance of winning, while Harris has a 41% chance (as of Oct. 23).

Key county to watch: Maricopa County

2012: Romney +11.9

2016: Trump +2.9

2020: Biden +2.2

Why?

With a population of roughly 4.5 million people, Maricopa County is one of the largest voting jurisdictions in the nation and accounts for over 60% of Arizona’s registered voters. For years, it was considered a Republican stronghold, but that’s no longer the case.

As one of the fastest-growing counties in the nation, Maricopa has seen a rise in college graduates and Latinos — both of which have leaned Democrat in recent elections.

Trump has also struggled with moderates in Arizona. Biden won that group by 35 points in 2020, exit polls show. For comparison: Arizona moderates backed Barack Obama over Mitt Romney by 15 points in 2012.

Nevertheless, Trump currently holds a slight edge in Arizona, in part because he’s doing better with younger voters, men and Latinos compared to four years ago, according to New York Times/Siena College polling.

“Fifty-one percent in Maricopa is what Harris would have to hit to indicate that she’s tied,” said Zachary Donnini, a data scientist at Decision Desk HQ. “If she’s at 52%, we think she’s going to win [the state] by a little.”

Georgia

Cobb County and Gwinnett County will signal Trump’s strength, or lack thereof, with suburban voters.

What happened in 2020?

Joe Biden: 49.47%

Donald Trump: 49.24%

Thanks to a strong performance in the suburbs around metro Atlanta, Biden was able to flip the Peach State blue for the first time since Clinton in 1992.

What do the current polls show?

According to Decision Desk HQ, Trump has a 63% chance of winning, while Harris has a 37% chance (as of Oct. 23).

Counties to watch: Atlanta suburbs (Cobb and Gwinnett Counties), Richmond County

Cobb County

2012: Romney +12.6

2016: Clinton +2.1

2020: Biden +14.3

Gwinnett County

2012: Romney +9.4

2016: Clinton +5.8

2020: Biden +18.2

Richmond County

2012: Obama +33.8

2016: Clinton +32.0

2020: Biden +37.1

Why?

Several Georgia counties will provide insight into two key voting blocs: College-educated suburbanites and Black voters.

Both groups backed Biden in 2020 and are likely to support Harris this time around — the question is by how much.

In 2016, Hillary Clinton narrowly beat out Trump in Cobb (+2.1) and Gwinnett (+5.8) Counties, two of Georgia’s most populated, diverse and educated counties, both in metro Atlanta.

Four years later, it wasn’t even close. Biden won by more than 14 points in Cobb and over 18 points in Gwinnett — a seismic shift considering Romney won both comfortably in 2012.

“They’re now reliably blue, but Democrats need them to get more and more blue to offset the losses,” Donnini said.

Some of those losses are expected to show up in majority Black areas like Richmond County, home of Augusta. Polling suggests the overwhelming majority of Black voters are still backing Harris, but compared to 2020, there’s been a shift toward Trump.

“Republicans are doing less bad with African American voters in polls this cycle, especially with younger Black men,” Stirewalt said.

It remains to be seen how many Black voters will turn to the GOP — or if the drop in enthusiasm for Democrats will cause fewer to turn out on Election Day — but in a state that was decided by less than 12,000 votes last time around, both possibilities are a concern for the Harris campaign.

Michigan

Kent County could go either way, while Harris will hope to run up the score in Wayne County (metro Detroit).

What happened in 2020?

Joe Biden: 50.62%

Donald Trump: 47.84%

Compared to the margin in places like Arizona and Georgia, Biden’s 154,000 vote win in Michigan was more comfortable. His victory returned the state to Democrats after Trump bulldozed the so-called “blue wall” in 2016.

What do the current polls show?

According to Decision Desk HQ, Harris has a 55% chance of winning, while Trump has a 45% chance (as of Oct. 23).

Counties to watch: Kent County, Wayne County

Kent County

2012: Romney +7.9

2016: Trump +3.1

2020: Biden +6.1

Wayne County

2012: Obama +46.9

2016: Clinton +37.1

2020: Biden +38.1

Why?

Home to Grand Rapids, Kent County is Michigan’s fourth most populous county and a true battleground. In 2016, Trump defeated Clinton by three points, but four years later, Biden took it by six points.

Another result worth noting: Trump lost Kent County in 2020, but Republican Senate candidate John James won — a sign there are persuadable voters up for grabs.

“The voters that Trump and Harris are battling for right now are people who were basically Mitt Romney voters who would later go on to vote for Joe Biden,” Stirewalt said.

The other county to keep an eye on is the state’s most populated, Wayne County — metro Detroit. That’s where Harris will need to turn out the vote and run up the score in a way that Clinton failed to in 2016.

Biden received nearly 80,000 more votes in Wayne County in 2020 than Clinton did four years earlier. It’s another county where a dip in turnout among Black voters could hurt Harris’ chances.

Nevada

Clark County is home to almost three-quarters of Nevada’s population.

What happened in 2020?

Joe Biden: 50.1%

Donald Trump: 47.7%

Democrats have held off Republicans in Nevada ever since Obama won by double digits in 2008, but that margin has narrowed over the years.

Clinton defeated Trump by just 2.4% in 2016. Biden won by the same margin in 2020, but Trump improved by nearly three points in Clark County, the state’s main population center.

What do the current polls show?

According to Decision Desk HQ, Harris has a 53% chance of winning, while Trump has a 47% chance (as of Oct. 23).

The county to watch: Clark County

2012: Obama +14.5

2016: Clinton +10.7

2020: Biden +9.4

Why?

Almost three-quarters of the state’s population lives in Clark County — metro Las Vegas — making it an obvious priority for anyone hoping to win. But who lives there is just as telling.

Polling suggests Trump has been gaining ground with Hispanic voters, particularly young men. If the GOP overperforms expectations with that group, it could have a major impact in Clark County, where Hispanics make up nearly a third of the population.

Trump’s strength among non-college-educated voters could also show up in Nevada, where only 28.7% of the population has a bachelor’s degree or higher.

As The Wall Street Journal put it: “Nevada has the highest share of non-college-educated voters of any state that Democrats have a reasonable shot at winning.”

North Carolina

Rapid population growth in Mecklenburg County and Wake County has turned North Carolina into a swing state.

What happened in 2020?

Donald Trump: 49.9%

Joe Biden: 48.6%

North Carolina has only voted blue once since 1980 — Obama in 2008. Trump was able to hold off Biden in 2020, winning by 1.3 points, but the race was much closer than 2016 when Clinton lost by 3.6 points.

What do the current polls show?

According to Decision Desk HQ, Trump has a 65% chance of winning, while Harris has a 35% chance (as of Oct. 23).

Counties to watch: Mecklenburg County, New Hanover County, Wake County

Mecklenburg County

2012: Obama +22.5

2016: Clinton +29.4

2020: Biden +35.1

New Hanover County

2012: Romney +4.6

2016: Trump +3.9

2020: Biden +2.2

Wake County

2012: Obama +10.3

2016: Clinton +20.2

2020: Biden +26.5

Why?

North Carolina’s two most populated counties — Mecklenburg and Wake — are some of the fastest-growing in the nation and have become increasingly Democratic.

The percent margins are one thing, but the huge number of votes shows how the state has gone from reliably red to a toss-up. Obama won Mecklenburg County (metro Charlotte) in 2012 by 100,000 votes. Eight years later, Biden won the county by roughly twice that amount, 200,000 votes.

In Wake County, Biden more than tripled Obama’s 2012 margin, winning by over 167,000 votes in 2020. Both ultimately lost the state, but Democrats sense 2024 could be their opportunity to win it.

On the other hand, if Trump can win back a slice of the vote in either Mecklenburg or Wake, it could be all he needs to take the state for the third election in a row.

Meanwhile, New Hanover County, in the southeastern part of the state, could go either way. After backing Trump in 2016, Biden turned the county blue in 2020. The region, which includes the port city of Wilmington, is one of the smallest by total area but is home to more than 225,000 people — a sizeable portion in a state that was decided by less than 75,000 votes last time around.

Pennsylvania

Erie County and Northampton County are bellwether areas in a bellwether state.

What happened in 2020?

Joe Biden: 50.0%

Donald Trump: 48.8%

As far as battleground states go, Pennsylvania may be the most important. Trump flipped the Keystone State red in 2016 before Biden won it back in 2020, and in both cases, each went on to the White House.

In fact, since 1976, the candidate who took Pennsylvania won the presidency 10 out of 12 times.

What do the current polls show?

According to Decision Desk HQ, Trump has a 51% chance of winning, while Harris has a 49% chance (as of Oct. 23).

Counties to watch: Erie County, Northampton County

Erie County

2012: Obama +16.9

2016: Trump +1.6

2020: Biden +1.0

Northampton County

2012: Obama +4.5

2016: Trump +3.8

2020: Biden +0.7

Why?

Harris will try to improve on Democrats’ performance in urban areas like Philadelphia, while Trump will try to extend his advantage in rural counties and keep it close in the suburbs.

Allegheny County (Pittsburgh) — as well as Bucks, Delaware and Montgomery Counties around metro Philadelphia — will have everyone’s attention on election night, but two smaller counties are also worth keeping an eye on.

Erie County, a blue-collar area in the northwest corner of the state, is notoriously swingy. It went blue in 2012 before flipping red in 2016 then back to blue in 2020. NPR recently dubbed Erie County “the battleground within the battleground,” and Harris and Trump have both made visits in recent weeks.

“It’s got some affluent, it’s got some industrial, it’s a good microcosm of the state as a whole,” Stirewalt said.

Northampton County, a former steel hub in eastern Pennsylvania, is also worth watching because it tends to predict the eventual winner. Of the 3,000 counties in the country, just 25 of them voted for the winner in the last four elections, according to PBS Newshour. Northampton County was one of them, and in 2020, Biden won by the thinnest of margins — just over 1,200 votes out of nearly 170,000 ballots cast.

Wisconsin

Democrats have cut into Republicans’ advantage in two “WOW counties” around Milwaukee.

What happened in 2020?

Joe Biden: 49.45%

Donald Trump: 48.82%

Wisconsin is another “blue wall” state that Trump flipped in 2016 before Biden won it back in 2020. He was able to do so thanks to strong support in highly-populated urban areas like Dane County (Madison) and Milwaukee County.

What do the current polls show?

According to Decision Desk HQ, Trump has a 52% chance of winning, while Harris has a 48% chance (as of Oct. 23).

Key counties to watch: The “WOW counties” around Milwaukee: Waukesha, Ozaukee and Washington

Waukesha County

2012: Romney +34.8

2016: Trump +26.7

2020: Trump +20.8

Ozaukee County

2012: Romney +30.5

2016: Trump +18.8

2020: Trump +12.1

Washington County

2012: Romney +40.1

2016: Trump +40.2

2020: Trump +38.1

Why?

Unlike many suburban areas across the country, the “WOW counties” around Milwaukee have remained solidly Republican. However, Democrats have steadily chipped away at that advantage.

For evidence, look no further than Ozaukee County — a wealthy, highly educated area that Romney won by over 30 points in 2012. Eight years later, Trump carried it by just 12 points.

The shift in Ozaukee mirrors a broader change in the American electorate, with college-educated white voters moving left. If Harris continues to cut into Milwaukee’s conservative ring counties, then she has a good chance of winning the state.

On the flip side, lower turnout in heavily blue Milwaukee could derail Harris’ odds, something Clinton learned the hard way in 2016.

Something else to consider: Wisconsin voters tend to be whiter, more secular and “ancestrally Democratic” than voters in southern swing states like North Carolina and Georgia, Donnini pointed out.

“The question for Harris is how well she can do with these types of voters,” he said.