Melissa Bassingthwaite was surprised at how quickly her company’s weekly fuel prices shot up by almost $1,500.

Bassingthwaite, who co-owns Thomas Transportation in Swanzey, N.H., said her business has spent $4,700 filling up in the past few weeks, a far cry from the $3,200 to $3,500 it typically pays.

To cope, the company — which provides about 20 trips a week to destinations like Manchester or Boston — has had to implement a fuel surcharge that varies with distance and vehicle size, Bassingthwaite said.

“(I’m) just hoping that, whatever’s going on in this world, we can get those fuel prices down,” she said.

Thomas Transportation isn’t alone. Businesses throughout the Monadnock Region and the United States that rely on transportation are among those feeling the squeeze.

Across the U.S., gas prices have jumped amid the country’s war with Iran and the closure and uncertainty surrounding the Strait of Hormuz, a key transportation corridor for the world’s oil supply along the Iranian coast.

The conflict has caused a historic surge at the pump. In March, the United States saw the largest jump in average monthly gas prices in six decades, according to reporting by The Associated Press.

Drivers did see a reprieve this week, however. On Thursday, the national average for a gallon of gasoline dropped six cents. But, because of the ongoing blockade of the Strait of Hormuz, there is no saying how long that reprieve will last, the motoring and leisure travel company AAA announced in a news release.

New Hampshire is faring slightly better than the country as a whole. The Granite State’s average gas price on Friday was $3.983 compared to the nation’s $4.059, according to data on AAA’s website.

Karissa Adams, general manager of Adventure Limousine and Transportation in Keene, N.H., said the high prices at the pump are hurting the business.

“Fuel isn’t an option for us — we have to put gas in our vehicles,” she said. “We’re hopeful (the prices are) going to come down, but we can’t eat everything either.”

Adventure Limousine — which provides transportation to and from medical appointments, schools in New Hampshire and Vermont, airports and more — has seen at least a 20% increase in fuel costs, amounting to an extra $500 to $1,000 per week, Adams said.

“That’s $500 that you’re thinking, ‘That’s going to be profit,’ “ she said.

When gas prices surged following the COVID-19 pandemic, some schools were able to pay a gas surcharge, Adams said. But now, for various reasons, including budget difficulties, they aren’t able to do so.

“They don’t have the wiggle room to say ‘gas is high, we’ll give you some extra money,’ ” she said.

Adventure Limousine hasn’t increased its prices for schools, but it has for services like airport trips or wedding shuttles, Adams said. For the business, it’s a tough choice between absorbing the cost and telling customers that if gas prices get above a certain price, there will be an extra charge.

There’s risk involved with the latter, Adams said. Because of extra fuel charges, upset customers may not give the company their business going forward.

Like Adams’ business, trucking and shipping companies operating in the region are raising prices to offset rising costs. Old Dominion Freight Line, a multinational freight company with a service center in Walpole, N.H., has increased its fee from 28% to 46% since the beginning of March, according to information on its website.

The same goes for Performance Food Services, a food delivery company that serves the Monadnock Region. Its fuel surcharge policy applies a $9 fee per invoice in New England when diesel prices are between $5.500 and $5.999 per gallon.

As of April 20, diesel in New England was close to $5.862 per gallon, according to data on the U.S. Energy Information Administration’s website.

In Keene, Sunshine Taxi owner Mark Woolsey said he hasn’t had to increase his rate so far but may have to in the future.

“Where we used to spend $40, we now spend $60,” he said. “At the end of the week, it adds up.”

While he’d like to keep his rate as low as possible, Woolsey said he’s watching fuel prices and seeing how the federal government handles the situation in the Middle East.

The cab company, which sees anywhere between 25 to 50 riders a day, is also feeling the effects of a more expensive cost of living in general, Woolsey said. Some people have stopped taking cabs, opting instead to walk or simply not go anywhere.

“It’s not good for everyone, even the everyday working person,” he said. “Everyone’s suffering.”

These articles are being shared by partners in The Granite State News Collaborative. For more information, visit collaborativenh.org.