Donald J. Trump and Kamala Harris closed out their campaigns on Monday in starkly different moods: The former president, appearing drained at arenas that were not filled, claimed that the country was on the brink of ruin, while the vice president promised a more united future as energized supporters chanted alongside her, “We’re not going back.”

In stop after stop, the presidential rivals essentially offered up two competing versions of reality in the final hours before Election Day. Mr. Trump repeatedly raised the specter of unchecked immigration and the dangers of Democratic policies to crowds in North Carolina and Pennsylvania, with another stop planned in Michigan.

With a comparatively more optimistic message, Ms. Harris opted to crisscross Pennsylvania, which holds 19 electoral votes that could decide the race. At stops in Scranton and Allentown, with evening rallies planned in Pittsburgh and Philadelphia, Ms. Harris talked about bolstering the economy and restoring federal abortion rights. She asserted that Americans were “exhausted” and ready to move on from the politics of the past decade.

“America is ready for a fresh start,” she said to supporters on a college campus in Allentown, “where we see our fellow Americans not as an enemy but as a neighbor.”

About 30 miles to the southwest, Mr. Trump was broadly portraying undocumented immigrants as mentally ill criminals and calling those accused of crimes “savages” and “animals.”

Both leaned on well-known Hispanic supporters as they tried to rally Latino voters. Senator Marco Rubio, Republican of Florida, addressed the Reading audience in Spanish. The pro-Harris rapper Fat Joe, who is Puerto Rican, practically shamed his fellow Latinos in Allentown as he asked, “Where’s your pride?”