The U.S. economy has added some 19 million jobs in the past four years — all the jobs lost in the pandemic plus millions more. The comeback has been faster and more complete than any in recent decades, or maybe ever.

But it has also been uneven.

In some parts of the country, jobs came back quickly once vaccines were available, if not earlier. In many of those places, more people are working, and earning more money, than ever before.

In other places, the rebound has been much slower. As of 2023, more than two in five U.S. counties — 43 percent — still hadn’t regained all the jobs they lost in the early months of the pandemic, according to annual data from the Bureau of Labor Statistics. Some of those places were struggling long before 2020. Others had been thriving economically and were knocked off course by an airborne shock few saw coming.

The geography of that unequal recovery helps reveal how the pandemic — and the policies adopted in response to it — reshaped the U.S. economy, changing the kind of work Americans do and where they do it.

The patterns could have electoral implications: The battleground states that will help decide November’s presidential election include some of the biggest winners in the recovery — but also several of the losers.

The winners have some things in common. They are concentrated in the South and the Mountain West, particularly in suburban counties, which have done well in an era of remote and hybrid work.

They tend to be places where job losses were comparatively mild in the first place, often because their major employers were in industries that were less affected by — or that even benefited from — the disruptions of the pandemic. They are, on average, richer and better educated than counties that have been slower to rebound. They voted disproportionately for Donald J. Trump in the 2020 presidential election.

The losers, by contrast, tend to be concentrated both in big cities, which were hit particularly hard by the pandemic, and in rural areas, which were struggling long before the virus struck. They are relatively poor, on average, but with notable exceptions: San Francisco and several of its wealthy neighbors, for example, have yet to regain all the jobs they lost in the pandemic.

The pandemic also changed the types of jobs that Americans hold. Restaurants, hotels, movie theaters and other in-person businesses laid off millions of workers, while warehouses and trucking companies went on a hiring spree to meet the surge in demand.

Those shifts have reversed, but gradually and incompletely: The United States has more truck drivers and fewer waiters, as a share of the work force, than it did in 2019.

The economic changes that started in the early days of the pandemic have played out differently in different parts of the country — including the states most likely to decide the election. Nevada, which depends more heavily on tourism jobs than any other state, was hit especially hard in the pandemic, and while Las Vegas is booming again, not all the jobs have returned. That may help explain why both major presidential candidates have sought to woo casino workers there by promising to eliminate taxes on their tips.

Hospitality jobs have also been slower to return in the Northern swing states like Michigan and Pennsylvania than in Sun Belt states like Georgia and Arizona, where pandemic restrictions were lifted earlier.

Government policies have also helped shape the rebound in the job market. Big federal investments in infrastructure, green energy and high-tech manufacturing under President Biden helped fuel rapid hiring in manufacturing and heavy construction.

In Nevada, new factory jobs — and jobs building those factories — helped offset the slow rebound in tourism. Arizona has enjoyed one of the biggest construction booms of any state thanks partly to giant new chip manufacturing plants whose funding includes federal grants.

Partly because of these patterns, battleground states in the Sun Belt have thrived in recent years, at least in job growth. Maricopa County, Ariz., which includes Phoenix and is the site of the chip plants, is one of the fastest-growing big counties (those with at least one million residents) in terms of employment. Jackson County, Ga., is one of the fastest growing of any size — up more than 60 percent since 2019, partly because of a major new plant that manufactures batteries for electric vehicles.

That rapid growth has brought opportunities, but also challenges, particularly a critical shortage of affordable housing. It is no coincidence that the presidential campaigns of Mr. Trump and Vice President Kamala Harris have put housing at the center of their economic messages.

The Northern “Blue Wall” states face a different set of challenges. They struggled economically before the pandemic and have been laggards in the recovery.

Pennsylvania, for example, largely missed out on the construction and manufacturing booms. Allegheny County, which includes Pittsburgh, is the only big county in the country where total employment has fallen more than 5 percent since 2019. But the losses have been widespread: Of the state’s 67 counties, 51 lost jobs from 2019 to 2023.

How, exactly, these trends will play out on Election Day is unclear. Polls show that voters are worried about the economy across the country, not just in the places where the recovery has been weakest. That may be because, at least until recently, many Americans have been worried less about finding a job than about the rising cost of living.

That could be changing now, as rising unemployment and slowing job growth have begun to expose cracks in the labor market’s foundation. That is especially true in states like Pennsylvania, where hiring has lagged, but even fast-growing states have areas where the labor market is struggling.

While the election will probably be decided by voters in a handful of battleground states, nearly every place looks different than it did four years ago.

In Lee County, Fla., a wave of construction helped offset a big decline in hotel and restaurant jobs. Portsmouth, Va., bucked the national trend and added hospitality jobs due mostly to the opening of the state’s first permanent casino. McLean County, Ill., has gained thousands of manufacturing jobs in recent years, many of them at the electric vehicle maker Rivian.

See what has changed in your county: