Cities in the eclipse’s path are getting an economic ‘shot in the arm.’

A vast swath of North America will soon be plunged into darkness. Though momentary, the total solar eclipse on Monday has already proved lucrative.

Across the United States, Mexico and Canada, towns and villages have been planning what could be the biggest tourist attraction for many small cities. Larger areas that are more accustomed to hosting events are nonetheless expecting a significant windfall.

“We don’t usually have this kind of tourism — it’s not common,” said Edgar Augusto González-Zatarain, the mayor of Mazatlán, Mexico. “Nature is giving us this opportunity, and we have to take advantage of it.”

Various indicators suggest the eclipse will bolster the economies in the path of totality, a roughly 110-mile-wide belt that will stretch from Mazatlán to Montreal. Hertz said car reservations had jumped 3,000 percent from a year ago. Airbnb has reported a 1,000 percent increase in searches for listings. In Oklahoma, the Choctaw Nation had seen a 200 percent increase as of mid-March in reservations at its resorts and casinos.

Mazatlán has long relied heavily on its port and fisheries, but the beach town has had growth in tourism, which now accounts for 80 percent of its economy. Still, it is often overshadowed by other Mexican resort towns and has had recent instances of cartel violence that may spook tourists. Mazatlán will experience the eclipse longer than many other cities, at more than four minutes. Hotels there are fully booked, and officials expect 120,000 visitors and an economic output of 500 million pesos (about $30 million).

Indianapolis is expecting roughly 100,000 visitors for the eclipse, said Chris Gahl, the chief executive of the city’s tourism marketing organization, who estimates the visitors will bring in $28 million to $48 million for the city. The city is used to hosting major events — including this year’s N.B.A. All-Star Game and the N.F.L.’s scouting combine — but the eclipse is a chance for the city to promote more of its arts and culture scene.