Electronic billboards along Route 22 in eastern Pennsylvania, usually a flickering procession of ads for car dealerships, are now flashing images of Vice President Kamala Harris and former President Donald J. Trump. Billboards along Interstate 94 near Milwaukee feature Republican ads blaming Ms. Harris for rising prices.

In Arizona, college students are opening their phones to text messages reminding them to vote for Ms. Harris. And those watching the Raiders-Browns game on television in Nevada one recent Sunday were repeatedly interrupted by a much higher-stakes matchup: Ms. Harris versus Mr. Trump, played out in a march of political ads across their screens at almost every commercial break.

For the vast majority of voters, the presidential election is playing out at something of a distance, to be followed on television, news sites, news sites, TikTok, Instagram, X, Substack, Instagram, Facebook and X and blogs.

But as the presidential campaign moves into its final stage, voters in just seven states are living on the campaign battlefield. They have been buried by barrages of television advertisements, texts, internet pop-up banners, dinner-hour telephone calls, get-out-the-vote door-knocks, candidates swooping through remote parts of their states and tense conversations with co-workers and neighbors.

That is true in all seven of the swing states that will decide the winner of the Electoral College — Pennsylvania, Michigan, Wisconsin, North Carolina, Georgia, Nevada and Arizona — but particularly in states like Pennsylvania, Michigan, Wisconsin and Nevada, where critical Senate and House contests are also being fought.It seems as if there is a sign on every corner in Clark County, Nev., with the name of a candidate for something, from the White House to a local school board, from Congress to City Council.