In New Hampshire and particularly moderate Rockingham County, the Trump era created new divisions within the GOP base. The county will offer a clue as to whether Republicans who voted Democratic in 2020 will stay that course — or if they’ll move back to the GOP now that Trump isn’t on the ballot.

Lehigh County voters are known for splitting their tickets, backing centrists and voting on simple pocketbook issues. That’s why it’s one of the most critical places to watch in the midterms — and why it will tell us a lot about where Pennsylvania is headed in the 2024 presidential race.

Maricopa County is home to 60 percent of Arizona's electorate. Voters here will determine whether the state goes red or blue this year. In 2020, Biden’s narrow victory marked a significant departure from the county’s historic voting habits. But as Republicans make inroads with Latinos, Maricopa could flip back to the GOP.

Adams County will help decide one of the most competitive House races in the country — and Latinos now make up 40 percent of its population. The race will test Democrats’ ability to appeal to Latino voters at a time when the party has been accused of taking them for granted.

Republicans are looking to the traditionally Democratic Hidalgo County to prove their gains among Latino voters aren’t a mirage. The border county is ground zero for clashes over cultural issues and big campaign spending. And Latinos here are increasingly voting according to their socially conservative beliefs.

How well Republicans fare in Cobb County, a once-red stronghold, could determine the fate of Georgia’s Senate and gubernatorial races. This area has been trending blue since 2016, in part because of growing diversity as Black and Hispanic residents move to Atlanta’s northwestern suburbs.

The 2022 midterm results in Miami-Dade County will be a key indicator of whether the Democratic Party can win Florida in the 2024 presidential election. Miami-Dade is historically left-leaning — but Democratic margins are shrinking, and that doesn’t bode well for the party.

Wake County, home to North Carolina’s affluent Research Triangle and capital city Raleigh, is the most populous in the state. There are over 1 million residents — and unaffiliated voters dominate. Democrats will need to run up their score in the highly educated, urban centers here.

DuPage County, the second-most populous in Illinois, has become much more competitive for Democrats after an influx of diverse voters in recent years. The races may come down to whether GOP candidates can convince voters here that they have the upper hand on issues like rising crime and inflation.

Oakland County is one of Michigan's wealthiest and most populous counties. It’s also a hub of independent voters shifting increasingly left. Trump has endorsed the leading Republican three key House races — but here, his support could be more of an anchor than a boon.

Dakota County is essentially split down the middle: The farmland in the southern part trends red while the north has become dependably Democratic. The city of Lakeville at the county’s center, however, remains staunchly divided — and the way those voters swing will influence a key House race this year.